England's chief medical officer has warned that schools could potentially close for two months or more in the UK if the spread of coronavirus intensifies.
Professor Chris Whitty warned that onward transmission between people who had not been to a coronavirus hotspot was "just a matter of time in my view".
His comments came as two more people in England were diagnosed with Covid-19, taking the UK total to 15 cases.
Coronavirus across the globe
Coronavirus across the globe
CORRECTS TO BROADWALK, INSTEAD OF BOARDWALK Tim Wirtz sits along the Hollywood Beach Broadwalk during the new coronavirus pandemic, Thursday, July 2, 2020, in Hollywood, Fla. In hard-hit South Florida, beaches from Palm Beach to Key West will be shut down for the Fourth of July holiday weekend. Restaurants and businesses along the Boardwalk will remain open. (AP Photo/Lynne Sladky)
A woman walks past benches taped off for social distancing outside a restaurant, Thursday, July 2, 2020, in La Habra, Calif. California's mood has gone from optimistic to sour as coronavirus cases and hospitalizations are on the rise heading into the July 4th weekend. Gov. Gavin Newsom has ordered bars and indoor restaurant dining closed in most of the state, many beaches are off limits, and he's imploring Californians to avoid holiday gatherings with family and friends. (AP Photo/Jae C. Hong)
A staff member talks to visitors to the Universal Studios Singapore theme park on the resort island of Sentosa in Singapore on July 3, 2020, as the attraction reopened after being temporarily closed due to concerns about the COVID-19 novel coronavirus. (Photo by Roslan RAHMAN / AFP) (Photo by ROSLAN RAHMAN/AFP via Getty Images)
Aspect of the La Boqueria market practically empty and without tourists, something unusual at this time of year in Barcelona, Spain on July 2, 2020. (Photo by Joan Valls/Urbanandsport /NurPhoto via Getty Images)
Aspect of the La Boqueria market practically empty and without tourists, something unusual at this time of year, in Barcelona, Spain on July 2, 2020. (Photo by Joan Valls/Urbanandsport /NurPhoto via Getty Images)
A tourist reacts as she arrives with others at Nikos Kazatzakis International Airport in Heraklion, Crete island, Greece, on Wednesday, July 1, 2020. The passengers most of them from Germany who came from Hamburg, with the first international flight to arrive in the island. Regional airports across Greece, including their tourist destination islands, began accepting direct international flights again on Wednesday, for the first time since flights were banned as part of the country's lockdown to prevent the spread of the coronavirus. (AP Photo/ Harry Nakos )
Tourists, arrive at Nikos Kazatzakis International Airport in Heraklion, Crete island, Greece, on Wednesday, July 1, 2020. The passengers most of them from Germany who came from Hamburg, with the first international flight to arrive in the island. Regional airports across Greece, including their tourist destination islands, began accepting direct international flights again on Wednesday, for the first time since flights were banned as part of the country's lockdown to prevent the spread of the coronavirus. (AP Photo/ Harry Nakos )
A man wearing a face mask and gloves to protect against coronavirus casts his ballot at a polling station in Moscow, Russia, Wednesday, July 1, 2020. The vote on the constitutional amendments that would reset the clock on Russian President Vladimir Putin's tenure and enable him to serve two more six-year terms is set to wrap up Wednesday. (AP Photo/Alexander Zemlianichenko)
Women wearing protective face masks pass an advertisement promoting awareness of the coronavirus outbreak at a shopping mall in Jakarta, Indonesia, Wednesday, July 1, 2020. The government of Indonesia's capital region is extending the first transition phase from large-scale social restrictions in Jakarta as the number of new confirmed coronavirus cases continues to rise. (AP Photo/Tatan Syuflana)
A woman, wearing a face mask and gloves to protect against coronavirus and observing social distancing guidelines, casts her ballot at a polling station with a portrait of former Soviet leader Josef Stalin on the wall in Volgograd, former Stalingrad, Russia, Wednesday, July 1, 2020. The vote on the constitutional amendments that would reset the clock on Russian President Vladimir Putin's tenure and enable him to serve two more six-year terms is set to wrap up Wednesday. (AP Photo/Dmitry Rogulin)
A woman, wearing a face mask to protect against coronavirus casts her ballot, observes social distancing guidelines, at a polling station in Grozny, Russia, Wednesday, July 1, 2020. Russia's vote on constitutional amendments that could allow President Vladimir Putin to extend his rule until 2036 entered its final day Wednesday amid widespread reports of pressure on voters and other irregularities. (AP Photo/Musa Sadulayev)
Spain's Prime Minister Pedro Sanchez gestures farewell to Portugal's Prime Minister Antonio Costa, right, as he departs after a ceremony to mark the reopening of the Portugal/Spain border in Elvas, Portugal, Wednesday, July 1, 2020. The border was closed for three and a half months due to the coronavirus pandemic. (AP Photo/Armando Franca)
People protest against Coronavirus trials in Africa, outside the University of the Witwatersrand in Johannesburg, South Africa, Wednesday, July 1, 2020. A protest against Africa’s first COVID-19 vaccine trial is underway as experts note a worrying level of resistance and misinformation around testing on the continent. (AP Photo/Themba Hadebe)
For demonstration purposes, an employee of the Centogene company takes a throat swab from a colleague at the airport in Frankfurt, Germany, Monday, June 29, 2020. In the future, people will be able to be tested for the corona virus within a few hours at Germany's first "Airport Corona Test" centre. (AP Photo/Michael Probst)
A security guard wearing a mask to curb the spread of the coronavirus watches over a gate in Beijing on Monday, June 29, 2020. Even as the world surpassed two sobering coronavirus milestones Sunday -- 500,000 confirmed deaths, 10 million confirmed cases -- and hit another high mark for daily new infections, China on Monday reported a further decline in new confirmed cases, with a total of just 12, including seven cases of domestic transmission in Beijing, where nearly 8.3 million people have now undergone testing in recent weeks. (AP Photo/Ng Han Guan)
A Greenpeace activists wearing protective gear to help curb the spread of the coronavirus arranges mannequins used to display posters during a protest outside the parliament in Jakarta, Indonesia, Monday, June 29, 2020. About a dozen of activists staged the protest against the government's omnibus bill on job creation that was intended to boost economic growth and create jobs, saying that it undermined labor rights and environmental protection. (AP Photo/Dita Alangkara)
An Indian man wearing a face mask as a precaution against the coronavirus sleeps outside closed shops during the reimposed lockdown in Gauhati, India, Monday, June 29, 2020. India has reported a new daily record of nearly 20,000 new infections as several Indian states reimpose partial or full lockdowns to stem the spread of the coronavirus. (AP Photo/Anupam Nath)
An Indian woman walks on a road painted with circles to help people maintain social distancing in Mumbai, India, Monday, June 29, 2020. Governments are stepping up testing and warily considering their next moves as the number of newly confirmed coronavirus cases surges in many countries. India reported more than 20,000 new infections on Monday. (AP Photo/Rajanish Kakade)
A sign on the door of the West Alabama Icehouse reads "Closed by the Governor", Monday, June 29, 2020, in Houston. Texas Gov. Greg Abbott shut down bars again and scaled back restaurant dining on Friday as cases climbed to record levels after the state embarked on one of America's fastest reopening. (AP Photo/David J. Phillip)
Empty tables are shown at the closed West Alabama Icehouse Monday, June 29, 2020, in Houston. Texas Gov. Greg Abbott shut down bars again and scaled back restaurant dining on Friday as cases climbed to record levels after the state embarked on one of America's fastest reopenings. (AP Photo/David J. Phillip)
A man wears a mask while voting, Monday, June 29, 2020, in Houston. Early voting for the Texas primary runoffs began Monday. (AP Photo/David J. Phillip)
A woman wearing a mask to curb the spread of the coronavirus holds her dog as they pass by a mall in Beijing on Monday, June 29, 2020. Even as the world surpassed two sobering coronavirus milestones Sunday -- 500,000 confirmed deaths, 10 million confirmed cases -- and hit another high mark for daily new infections, China on Monday reported a further decline in new confirmed cases. (AP Photo/Ng Han Guan)
A priest wearing a protective mask to avoid COVID-19 spread stands in St. Peter's Square during the Angelus prayer celebrated by Pope Francis from his studio window on the occasion of the Feast of Rome's Patrons Saints Peter and Paul, at the Vatican, Monday, June 29, 2020. (AP Photo/Riccardo De Luca)
Activists of Communist Party of India Marxist wearing face shields and hold placards during a protest asking the state government to increase testing and free treatment for all COVID-19 patients in Hyderabad, India, Monday, June 29, 2020. Governments are stepping up testing and warily considering their next moves as the number of newly confirmed coronavirus cases surges in many countries. India reported more than 20,000 new infections on Monday. (AP Photo/Mahesh Kumar A.)
Financial union members wearing face masks to help protect against the spread of the new coronavirus attend a rally against government's financial policy in front of the Financial Supervisory Service in Seoul, Monday, June 29, 2020. (AP Photo/Ahn Young-joon)
A roadside vendor sells mobile phone covers as she waits for customers at a closed market amid concerns over the spread of the COVID-19 coronavirus in Leh, the joint capital of the union territory of Ladakh, on June 28, 2020. (Photo by Tauseef MUSTAFA / AFP) (Photo by TAUSEEF MUSTAFA/AFP via Getty Images)
PARIS, FRANCE - JUNE 28: A man walks past electoral posters against Paris Mayor, Socialist Anne Hidalgo, who is fighting for a second term, as Parisians go to the polls today in the second round of Municipal elections on June 28, 2020 in Paris, France. The second-round vote, which was postponed by more than three months due to the coronavirus pandemic has forced candidates to conduct remote campaigns as restrictions have meant they were unable to canvas door to door, shake hands or distribute campaign material. (Photo by Kiran Ridley/Getty Images)
MELBOURNE, AUSTRALIA - JUNE 28: A general view of a pop-up Covid-19 testing tent during a COVID-19 testing blitz in the suburb of Broadmeadows on June 28, 2020 in Melbourne, Australia. Victoria's confirmed COVID-19 infection numbers continue to rise, with 49 new coronavirus cases recorded overnight. Health authorities are continuing on a testing blitz in Melbourne suburbs that have been identified as community transmission hotspots for coronavirus. Restrictions in Victoria have been tightened in response to the spike in new cases across the state with premier Daniel Andrews extending the current state of emergency for at least four weeks to allow police the power to enforce social distancing rules. (Photo by Asanka Ratnayake/Getty Images)
WARSAW, POLAND - JUNE 28: A father and son wearing protective face masks cast a ballot in the Polish presidential election during the coronavirus pandemic on June 28, 2020 in Warsaw, Poland. The two lead candidates are current Polish President Andrzej Duda of the socially conservative Law and Justice (PiS) party and Warsaw Mayor Rafal Trzaskowski of the of the centrist Civic Platform (PO). Today’s election to determine the next Polish president, who serves a five-year term, was originally scheduled for May but was delayed due to the coronavirus pandemic. (Photo by Sean Gallup/Getty Images)
Iran announced new measures to combat the spread of the novel coronavirus as the country counted 144 new fatalities, its highest death toll for a single day in almost three months (AFP Photo/ATTA KENARE)
TOPSHOT - Roadside vendors carry vegetables at a closed market amid concerns over the spread of the COVID-19 coronavirus in Leh, the joint capital of the union territory of Ladakh, on June 28, 2020. (Photo by Tauseef MUSTAFA / AFP) (Photo by TAUSEEF MUSTAFA/AFP via Getty Images)
A brig with scarlet sails on the Finnish Gulf coast during a rehearsal for the the Scarlet Sails festivities marking school graduation which will take place on June 27 in St.Petersburg, Russia, early Friday, June 26, 2020. This year the festival will not be held in the city center, but on the Finnish Gulf. Due to the coronavirus pandemic, there will be no spectators but the event will be broadcast on television. (AP Photo/Dmitri Lovetsky)
Sri Lankan Municipal health workers spray disinfectant to another colleague who conducted blood tests for COVID-19 antibody tests at a market place in Colombo, Sri Lanka, Friday, June 26, 2020. (AP Photo/Eranga Jayawardena)
A brig with scarlet sails travels on the Finnish Gulf coast during a rehearsal for the the Scarlet Sails festivities marking school graduation which will take place on June 27 in St.Petersburg, Russia, early Friday, June 26, 2020, with the setting moon in the background. This year the festival will not be held in the city center, but on the Finnish Gulf. Due to the coronavirus pandemic, there will be no spectators but the event will be broadcast on television. (AP Photo/Dmitri Lovetsky)
Tubers prepare to float the Comal River despite the recent spike in COVID-19 cases, Thursday, June 25, 2020, in New Braunfels, Texas. Texas Gov. Greg Abbott said Wednesday that the state is facing a "massive outbreak" in the coronavirus pandemic and that some new local restrictions may be needed to protect hospital space for new patients. (AP Photo/Eric Gay)
Staff of a cinema spray disinfectant at the cinema hall to prepare for reopening on July 1 in Kuala Lumpur, Malaysia, Friday, June 26, 2020. Malaysia entered the Recovery Movement Control Order (RMCO) after three months of coronavirus restrictions. (AP Photo/Vincent Thian)
Seguidores del Liverpool festejan con bengalas frente al estadio Anfield, el jueves 25 de junio de 2020, cuando el equipo se coronó en la Liga Premier con una victoria del Chelsea sobre el Manchester City (AP Foto/Jon Super)
People wearing face masks shop for accessories at a mobile shop in Hyderabad, India, Thursday, June 25, 2020. India is the fourth hardest-hit country by the pandemic in the world after the U.S., Russia and Brazil. (AP Photo/Mahesh Kumar A.)
A vendor wearing a face mask waits for customers under a flyover bridge in Hyderabad, India, Thursday, June 25, 2020. India is the fourth hardest-hit country by the pandemic in the world after the U.S., Russia and Brazil. (AP Photo/Mahesh Kumar A.)
A member of the election commission checks the temperature of a voter, both wearing face masks to protect against coronavirus at a polling station in Moscow, Russia, Thursday, June 25, 2020. Polls have opened in Russia on Thursday for a week-long vote on a constitutional reform that would allow President Vladimir Putin to stay in power until 2036. (AP Photo/Alexander Zemlianichenko)
Voters wearing face masks to protect against coronavirus stand in front of a ballot box, observing social distancing guidelines, at a polling station at a school in Moscow, Russia, Thursday, June 25, 2020. Polls have opened in Russia on Thursday for a week-long vote on a constitutional reform that would allow President Vladimir Putin to stay in power until 2036. (AP Photo/Alexander Zemlianichenko)
A Yemeni pharmacist wearing a protective face mask serves his customers behind a glass shield installed as a precautionary measure against the spread of the coronavirus at a pharmacy in Sanaa, Yemen, Thursday, June 25, 2020. (AP Photo/Hani Mohammed)
Senegalese students wear masks to curb the spread of the coronavirus as they return to classes on the first day back after more than three months away, at the Sacre Coeur college in Dakar, Senegal Thursday, June 25, 2020. (AP Photo/Sylvain Cherkaoui)
Senegalese students learn about health and the coronavirus during an English lesson as they returned to classes on the first day back after more than three months away, at the Sacre Coeur college in Dakar, Senegal Thursday, June 25, 2020. (AP Photo/Sylvain Cherkaoui)
Hospital workers demonstrate in front of the Robert Debre hospital, in Paris Thursday, June 25, 2020. French hospital workers are protesting to demand better pay and more investment in France's public hospital system, which is considered among the world's best but struggled to handle a flux of virus patients after years of cost cuts. (AP Photo/Christophe Ena)
Hospital workers demonstrate in front of the Robert Debre hospital, in Paris Thursday, June 25, 2020. French hospital workers are protesting to demand better pay and more investment in France's public hospital system, which is considered among the world's best but struggled to handle a flux of virus patients after years of cost cuts. Banner reads «Hospital workers. Users. All united for our health». (AP Photo/Christophe Ena)
Protesters wearing protective masks and maintaining social distancing attend a metalworkers demonstration asking for measures against economic crisis worsened by the Covid-19 pandemic, in Rome, Thursday, June 25, 2020. (AP Photo/Riccardo De Luca)
Police officers stop motorcyclists from entering a restricted area that is sealed off to control the spread of the coronavirus, in Lahore, Pakistan, Thursday, June 25, 2020. (AP Photo/K.M. Chaudhry)
People queue up prior to visit the Eiffel Tower, in Paris, Thursday, June 25, 2020. The Eiffel Tower reopens after the coronavirus pandemic led to the iconic Paris landmark's longest closure since World War II. (AP Photo/Thibault Camus)
WUHAN, CHINA - JUNE 25: (CHINA OUT) People wear face masks while uses a iPhone at the Auto Fair during Dragon Boat Festival holiday on June 25, 2020 in Wuhan, China. Since June 13 the response level of public health emergencies in Hubei Province has been reduced to level 3. Wuhan's health commission said that the city had no asymptomatic cases as of June 15, and there are no more close contacts under medical observation. (Photo by Getty Images)
Passengers travel wearing facemasks on a tram in Zagreb on June 25, 2020, as the wearing of masks on public transport in Croatia became mandatory on June 23, due to an increase of coronavirus infections after the relaxation of lockdown conditions. (Photo by DENIS LOVROVIC / AFP) (Photo by DENIS LOVROVIC/AFP via Getty Images)
MADRID, SPAIN - JUNE 25: The minister of Defense, Margarita Robles, is seen during the closing and recognition ceremony of the 'Balmis' operation, at the Retamares Base at the town of Pozuelo de Alarcón, on June 25, 2020 in Madrid, Spain. The 'Balmis' operation has been the largest military deployment in Spain in peacetime. During the last 98 days of state of alarm the military has carried out almost 20,000 interventions to combat Covid-19 in a total of 2,300 locations, throughout the territory. (Photo by Eduardo Parra/Europa Press via Getty Images) (Photo by Europa Press News/Europa Press via Getty Images)
Spain´s King Felipe VI (2R) and Queen Letizia (2L) walk at Palma Beach in Palma de Mallorca on June 25, 2020, during their national tour after the national lockdown to stop the spread of the novel coronavirus was lifted. (Photo by JAIME REINA / AFP) (Photo by JAIME REINA/AFP via Getty Images)
Dutch King Willem-Alexander visits Nedschroef in Helmond on June 25, 2020. - The visit focuses on the impact of the coronavirus crisis on the automotive industry. (Photo by Rob ENGELAAR / various sources / AFP) / Netherlands OUT (Photo by ROB ENGELAAR/ANP/AFP via Getty Images)
MOSCOW, RUSSIA - JUNE 24, 2020: A Russian soldier wears a face mask in Lenin Square during a Victory Day military parade marking the 75th anniversary of the victory in World War II. Victory Day parades across Russia have been postponed from 9 May to 24 June due to restrictions imposed to prevent the spread of the novel coronavirus. Kirill Kukhmar/TASS (Photo by Kirill Kukhmar\TASS via Getty Images)
Medics from Beijing Fengsheng Special Hospital of Traditional Medical Traumatology and Orthopaedics prepare for their shift at the Jinrong Street testing site, inside a room where a Communist Party flag and a piece of red tissue with words that reads "Beijing Fengsheng Special Hospital of Traditional Medical Traumatology and Orthopaedics" (back on wall) in Beijing on June 24, 2020. - China reported 12 new cases of COVID-19, including seven cases domestic cases in Beijing. (Photo by NICOLAS ASFOURI / AFP) (Photo by NICOLAS ASFOURI/AFP via Getty Images)
People leave a Costco outlet with a trolley full of toilet paper as fears of a second wave of COVID-19 have sparked a rush on some supermarket items in Melbourne on June 24, 2020. - Major supermarkets in the state of Victoria have reimposed buying limits on toilet paper and other essentials after a renewed escalation in demand sparked fears of a return to scenes of panic-buying seen early in the pandemic. (Photo by William WEST / AFP) (Photo by WILLIAM WEST/AFP via Getty Images)
VLADIVOSTOK, RUSSIA - JUNE 24, 2020: A woman takes a picture as WWII-era military hardware from the collection of the 20th Century Hardware in Primorsky Territory patriotic club takes part in a Victory Day military parade marking the 75th anniversary of the victory in World War II. Victory Day parades across Russia have been postponed from 9 May to 24 June due to restrictions imposed to prevent the spread of the novel coronavirus. Yuri Smityuk/TASS (Photo by Yuri Smityuk\TASS via Getty Images)
A woman reacts as she has her nasal swab sample collected by a health worker during a mass test for the new coronavirus at the local district office in Tanah Abang in Jakarta, Indonesia, Sunday, June 21, 2020. (AP Photo/Dita Alangkara)
Afghan yoga enthusiasts perform to mark International Yoga Day amid the COVID-19 pandemic lockdown, on the outskirts of Kabul, Afghanistan, Sunday, June 21, 2020. (AP Photo/Rahmat Gul)
Sergej Trifunovic, the leader of the Free Citizens Movement (PSG), an opposition party, casts his ballot for the parliamentary election at a polling station in Belgrade, Serbia, Sunday, June 21, 2020. Serbia's ruling populists are set to tighten their hold on power in a Sunday parliamentary election held amid concerns over the spread of the coronavirus in the Balkan country and a partial boycott by the opposition. (AP Photo/Marko Drobnjakovic)
A man wearing a mask as a precaution against coronavirus performs rituals at Sangam, the confluence of rivers the Ganges and the Yamuna during solar eclipse in Prayagraj, India, Sunday, June 21, 2020. (AP Photo/Rajesh Kumar Singh)
A lifeguard stand is decorated with a large mask to remind people to wear masks as precaution against the new coronavirus at a beach in Tel Aviv, Israel, Sunday, June 21, 2020. (AP Photo/Sebastian Scheiner)
People wearing face masks to protect against the new coronavirus take photos of a partial solar eclipse near the Forbidden City in Beijing, Sunday, June 21, 2020. (AP Photo/Mark Schiefelbein)
A man sits wearing a mask as a precaution against coronavirus as Hindu devotees perform rituals at Sangam, the confluence of rivers the Ganges and the Yamuna during solar eclipse in Prayagraj, India, Sunday, June 21, 2020. (AP Photo/Rajesh Kumar Singh)
A man, wearing a protective face mask, pushes a dolly filled with empty containers, as he and a child go in search of water in Caracas, Venezuela, Saturday, June 20, 2020, during a relaxation of restrictive measures amid the new coronavirus pandemic. (AP Photo/Ariana Cubillos)
Bride Jazmin Sanabria and her groom Joel Adorno, wearing protective face masks amid the new coronavirus pandemic, walk down the aisle in the first wedding ceremony since 101 days of quarantine at the Virgen del Rosario church, in Luque, Paraguay, Saturday, June 20, 2020. The government is easing restrictive measures, authorizing the opening of some stores, restaurants and churches that had been closed since March 10, as part of a plan coined, "Intelligent Quarantine." (AP Photo/Jorge Saenz)
Women buy vegetables through a protective plastic due to COVID-19, in a street market in Barranco neighborhood, in Lima, Peru, Saturday, June 20, 2020. (AP Photo/Rodrigo Abd)
People participate in an anti-government demonstration one week ahead of the presidential election in Warsaw, Poland, Saturday, June 20, 2020.(AP Photo/Czarek Sokolowski)
ISTANBUL, TURKEY - JUNE 18: Kid mannequins with masks are placed by the tables diagonally to protect customers' social distance as part of coronavirus (Covid-19) precaution at Beyoglu district in Istanbul, Turkey on June 18, 2020. (Photo by Emrah Yorulmaz/Anadolu Agency via Getty Images)
Firefighters wearing protective suits spray disinfectant at National Monument area to prevent the spread of the coronavirus disease (COVID-19)
WASHINGTON, DC - MAY 20: White House Press Secretary Kayleigh McEnany speaks during a news briefing in the James Brady Press Briefing Room of the White House May 20, 2020 in Washington, DC. McEnany discussed various topics including the Trump Administration’s handling of the coronavirus (COVID-19) pandemic. (Photo by Alex Wong/Getty Images)
ACEH, INDONESIA - JUNI 18 2020 : Indonesian brides and men wear face masks as required during the wedding, amid fears of a COVID-19 coronavirus outbreak, in Lhokseumawe, on Juni 18, 2020, Aceh Province, Indonesia.- PHOTOGRAPH BY Fachrul Reza / Barcroft Studios / Future Publishing (Photo credit should read Fachrul Reza/Barcroft Media via Getty Images)
dpatop - 14 October 2020, Brazil, Sao Paulo: Cemetery workers in protective suits shoveling earth at the Vila Formosa cemetery in the Brazilian city of Sao Paulo in the middle of the Corona pandemic. Photo: Lincon Zarbietti/dpa (Photo by Lincon Zarbietti/picture alliance via Getty Images)
Coronavirus infection (COVID-19) is still continuing in the country, a guard of Gyeongbokgung Palace wears a protective mask with a goblin pattern at the entrance of the palace, which is currently not being opened to the public due to Covid-19 in Seoul, South Korea on June 18, 2020. (Photo by Chris Jung/NurPhoto via Getty Images)
YEKATERINBURG, RUSSIA - JUNE 16, 2020: Servicewomen rehearse a military parade marking the 75th anniversary of Victory in WWII. Held annually on 9 May, the 2020 parade was rescheduled by Russia's President Vladimir Putin for 24 June amid the coronavirus pandemic. Donat Sorokin/TASS (Photo by Donat Sorokin\TASS via Getty Images)
BEIJING, June 16, 2020 -- Members of the Beijing Blue Sky Rescue(BSR) team conduct disinfection at the Yuegezhuang wholesale market in Beijing, capital of China, June 16, 2020. Beijing has disinfected 276 farm produce markets and closed 11 such underground and semi-underground markets as of 6 a.m. Tuesday to better curb the spread of the novel coronavirus, Chen Yankai, deputy director of the municipal market supervision bureau, told a press conference on Tuesday.
A total of 33,173 catering service providers have also been disinfected, Chen added.(Photo by Chen Zhonghao/Xinhua via Getty) (Xinhua/Chen Zhonghao via Getty Images)
TOPSHOT - A vendor walks through a flower market after the government eased a nationwide lockdown imposed as a preventive measure against the COVID-19 coronavirus, in Kolkata on June 17, 2020. (Photo by Dibyangshu SARKAR / AFP) (Photo by DIBYANGSHU SARKAR/AFP via Getty Images)
A member of a university laboratory wearing protective gear is pictured at a community health centre as the government collects swab samples from residents to test for the COVID-19 coronavirus in Banda Aceh on June 17, 2020. (Photo by CHAIDEER MAHYUDDIN / AFP) (Photo by CHAIDEER MAHYUDDIN/AFP via Getty Images)
Commuters have their temperatures checked as they arrive at the entrance to Hong Kong's Disneyland on June 17, 2020, a day before the theme park's doors reopen following nearly five months of closure in a fresh boost for a city that has largely managed to defeat the COVID-19 coronavirus. - It is just the second Disneyland around the world to resume services during the pandemic after Shanghai turned its lights and rides back on last month. (Photo by Anthony WALLACE / AFP) (Photo by ANTHONY WALLACE/AFP via Getty Images)
A waiter answers a client at La Coupole restaurant, Monday, June 15, 2020 in Paris. Paris is rediscovering itself, as its cafes and restaurants reopen for the first time since the fast-spreading virus forced them to close their doors March 14. Restaurants outside the Paris region opened earlier this month, and Paris cafes were allowed to serve people outside but not open their doors. After three months of losses, some restaurateurs fear it will take a long time for business to come back. (AP Photo/Christophe Ena)
BEIJING, CHINA - JUNE 16: A nurse wearing a protective suit and mask takes a nucleic acid test for COVID-19 from a person who either visited or lives near the Xinfadi Market at a testing facility at a Sport Center on June 16, 2020 in Beijing, China. From June 11 to June 16, Beijing reported a total of 106 new confirmed cases of coronavirus (covid-19), the number of new infection has risen after no new cases for nearly two months. (Photo by Lintao Zhang/Getty Images)
Cemetery workers wearing protective gear against the new coronavirus, walk after carrying the coffin of 72-year-old Monica Lagos to her grave at the Manantial cemetery in Santiago, Chile, Monday, June 15, 2020. According to her grandaughter Ninoska Vasquez, who works as an assistant at a health center, Lagos died from complications related to COVID-19. (AP Photo/Esteban Felix)
A commuter wearing a goggle and protective face mask to help curb the spread of the new coronavirus sits on the seat of a subway train in Beijing, Tuesday, June 16, 2020. China reported several dozen more coronavirus infections Tuesday as it increased testing and lockdown measures in parts of the capital to control what appeared to be its largest outbreak in more than two months. (AP Photo/Andy Wong)
BOGOTA, COLOMBIA - JUNE 12: A personnel wears a face shield as a preventive measure against the coronavirus (COVID-19) pandemic at the Hayuelos Mall in Bogota, Colombia, on June 12, 2020. After almost 3 months of imposing the semi-lockdown regulations to curb the spread of coronavirus, the Colombian government started the transition to new normal with opening offices, shopping malls, and other places on conditions of following health protocols and maintaining social distance. (Photo by Juan Jaiver Torres Padilla/Anadolu Agency via Getty Images)
A German tourist takes a sunbath at the Riu Concordia hotel swimming pool in Palma de Mallorca, Spain, Monday, June 15, 2020. Borders opened up across Europe on Monday after three months of coronavirus closures that began chaotically in March. But many restrictions persist, it's unclear how keen Europeans will be to travel this summer and the continent is still closed to Americans, Asians and other international tourists. (AP Photo/Joan Mateu)
Workers walk across a banquet hall which is generally used for weddings that has been converted to makeshift coronavirus hospital as the Indian capital struggles to contain a spike in cases. in New Delhi, India, Monday, June 15, 2020. India is the fourth hardest-hit country by the COVID-19 pandemic in the world after the U.S., Russia and Brazil. (AP Photo/Manish Swarup)
A student arrives at school for the first day of class since the lockdown to curb the spread of the new coronavirus pandemic in Montevideo, Uruguay, Monday, June 15, 2020. Some children in urban areas returned to school Monday. (AP Photo/Matilde Campodonico)
15 June 2020, Yemen, Sanaa: Medical workers talk while checking on patients in the intensive care unit of a hospital, where coronavirus (Covid-19) patients are treated. Photo: Hani Al-Ansi/dpa (Photo by Hani Al-Ansi/picture alliance via Getty Images)
FRANKFURT AM MAIN, GERMANY - JUNE 15: A staff member of the Balearic Islands Tourist Office holts a fakt sheeet for the tourists waiting to check in for a TUIfly flight to Mallorca at Frankfurt Airport on the first day that package tours are resuming since March during the coronavirus pandemic on June 15, 2020 in Frankfurt, Germany. The travellers are participating in a test project in which the Spanish government is allowing up to 11,000 tourists from Germany to travel to the Balearic Islands. Spain, which was hit especially hard by Covid-19, has begun to ease pandemic lockdown measures, though tourist travel is still restricted. The project is meant to test the viability of reopening the country to tourism. (Photo by Thomas Lohnes/Getty Images)
Shoppers queue outside Zara in Belfast, northern Ireland, Monday, June 15, 2020. After three months of being closed under coronavirus restrictions, shops selling fashion, toys and other non-essential goods are being allowed to reopen across England for the first time since the country went into lockdown in March. (Liam McBurney/PA via AP)
Knowsley Safari Park re-opens following the outbreak of the coronavirus disease (COVID-19) in Knowsley
fans applause inside the car during the performance of Punkrock band Rogers in Auto concert in Bonn, Germany, on June 13, 2020. (Photo by Ying Tang/NurPhoto via Getty Images)
A man looks out from his window in Caracas, Venezuela, Saturday, June 13, 2020. Authorities in Venezuela are extending a quarantine keeping millions of residents across the South American nation at home through mid-July to control the spread of the new coronavirus. (AP Photo/Ariana Cubillos)
Passengers walk through the airport wearing face masks amid the COVID-19 pandemic in Cancun, Mexico, Saturday, June 13, 2020. In Quintana Roo state, where Cancun is located, tourism is the only industry there is, and Cancun is the only major Mexican resort to reopen so far. (AP Photo/Victor Ruiz)
A member of Black Lives Matter movement, wearing a protective mask against the spread of coronavirus, raises her fist during a protest in central London, Saturday, June 13, 2020. British police have imposed strict restrictions on groups protesting in London Saturday in a bid to avoid violent clashes between protesters from the Black Lives Matter movement, as well as far-right groups that gathered to counter-protest.(AP Photo/Kirsty Wigglesworth)
Protesters hold signs during a demonstration calling for the defunding of the police department Saturday, June 13, 2020, in Philadelphia, over the death of George Floyd, who died after being restrained by Minneapolis police officers. (AP Photo/David Goldman)
Greek Prime Minister Kyriakos Mitsotakis used the island of Santorini to announce that Greece is 'ready' to welcome tourists, on June 13, 2020 (Photo by Aggelos Barai/NurPhoto via Getty Images)
Gente con mascarillas para protegerse del coronavirus mientras viajan en metro en Taipei, Taiwán, el sábado 13 de junio de 2020. (AP Foto/Chiang Ying-ying)
Workers in protective suits direct people who was either living surrounding the Xinfadi wholesale market or have visited to the market to get a nucleic acid test at a stadium in Beijing, Sunday, June 14, 2020. China is reporting its highest daily total of coronavirus cases in two months after the capital's biggest wholesale food market was shut down following a resurgence in local infections. (AP Photo/Andy Wong)
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Speaking at a Nuffield Trust summit in London, Prof Whitty said: "If this becomes a global epidemic, then the UK will get it, and if it does not become a global epidemic, the UK is perfectly capable of containing and getting rid of individual cases leading to onward transmission."
But he said onward transmission was "just a matter of time in my view", adding: "If it is something which is containable, the UK can contain it. If it is not containable, it will be non-containable everywhere and then it is coming our way."
He said there could be a potential "social cost" if the virus intensifies which could include actions such as reducing mass gatherings and closing schools.
He said he was not saying that would happen, but that the effectiveness of such strategies would have to be weighed up against social cost.
"One of the things that's really clear with this virus, much more so than flu, is that anything we do we're going to have to do for quite a long period of time, probably more than two months," he said.
"The implications of that are non-trivial, so we need to think that through carefully.
"This is something we face as really quite a serious problem for society potentially if this goes out of control.
"It may not, but if it does globally then we may have to face that."
One of the new UK cases on Thursday – a parent at a Buxton primary school in Derbyshire – contracted the virus in Tenerife, where 168 Britons have been confined to a hotel on the south-west of the island.
The other person contracted the virus in Italy, which has become the worst affected country in Europe with more than 400 cases and 14 deaths.
One patient has been taken to the specialist infectious diseases centre at the Royal Liverpool Hospital and the other to the Royal Free Hospital in London.
Burbage Primary School in Buxton remains closed until March 2.
Dr Fu-Meng Khaw, centre director for Public Health England (PHE) East Midlands, said the agency was contacting people who had close contact with the patient, and confirmed they were infected whilst in Tenerife.
He added: "Close contacts will be given health advice about symptoms and emergency contact details to use if they become unwell in the 14 days after contact with the confirmed cases.
"This tried and tested method will ensure we are able to minimise any risk to them and the wider public.
"We are aware that Burbage Primary School in Buxton has taken the decision to close today.
"My team have spoken to the school, assessed the risk and confirmed that there is currently no information to suggest that there is any increased health risk to any pupils or staff at the school and no public health reason to remain closed at the current time."
Buxton Medical Practice in Derbyshire, a two-minute drive from the school, also urged patients not to attend for appointments on Thursday due to the confirmed case.
Meanwhile, sources told the PA news agency that around 50 of the 168 Britons confined to the H10 Costa Adeje Palace in Tenerife will be allowed to leave if they wish.
The group arrived on Monday, after the four guests who went on to be diagnosed with coronavirus had already left.
Overall, 130 guests from 11 countries have been told they can leave by Spanish authorities.
Britons have expressed frustration with quarantine measures at the hotel, with guests walking around the site without face masks and sharing meals at the buffet.
One guest told PA that an aqua-gym class was held in the hotel pool on Thursday, while another said they had witnessed a cocktail-making class.
TV doctor Hilary Jones has blasted isolation measures at the hotel and warned that guests may need to stay on well beyond an initial 14 days.
The Foreign Office has no current plans to repatriate Britons from the hotel but is keeping the situation under review.
Professor Yvonne Doyle, medical director at PHE, said it had sent a health protection specialist to Tenerife "to work with the Spanish authorities to better understand the public health measures that have been put in place in the hotel".
So far in the UK, 7,690 people have been tested for the virus and of the 15 to have tested positive, eight have so far been discharged from hospital.
Globally, Denmark was among those countries confirming their first cases on Thursday, while Saudi Arabia has stopped Muslim pilgrims entering to worship at the holy cities of Mecca and Medina.
In Japan, all schools will close for several weeks, while US experts have reported the first case of unknown origin, which suggests the virus is spreading there.
In China, where the virus originated, 78,497 cases have been reported, including 2,744 deaths.
After Brazil confirmed Latin America's first case on Wednesday, the virus has reached every continent except Antarctica.
World Health Organisation (WHO) director-general, Dr Tedros Ghebreyesus, told a press conference in Geneva on Thursday that coronavirus has the potential to become a global pandemic but that this stage had not been reached.
Public health advice remains to wash hands with soap, not rub the face and maintain a distance from people who are coughing and sneezing, he said.
Dr Michael Ryan, executive director of the WHO Health Emergencies Programme, said the idea that the virus is mostly being transmitted by people without symptoms is a "myth".
He added: "Data from China does not suggest that asymptomatic people are becoming the driving force behind this."