Positive coronavirus tests in the UK have hit a two-month high, following an outbreak at a sandwich factory in Northampton.
The daily number published on Friday for positive tests – 1,441 lab-confirmed cases – is the highest since June 14.
Figures show 104 new cases in Northampton were recorded on Monday and another 104 the following day, pushing the town to the top of the list of highest weekly rates in England.
Northampton's rate shot up to 115.8 cases per 100,000 people in the seven days to August 11 – from 34.7 in the previous seven days to August 4.
On Thursday Northamptonshire County Council said 292 people had tested positive for Covid-19 after an outbreak at Greencore sandwich factory.
Parts of the north of England which have been under local lockdowns for a fortnight have been told they are facing a third week of restrictions.
Households in areas of the North West, West Yorkshire, East Lancashire and Leicester cannot mix indoors, unless they are in a support bubble, and limits remain on numbers meeting outside.
While the rest of England prepares to reopen venues such as casinos, bowling alleys and conference halls from Saturday, as well as have wedding receptions of up to 30 people, the national easing – which had been delayed from August 1 – will not apply to Greater Manchester, West Yorkshire, East Lancashire or Leicester.
There has been a continued rise in cases in Oldham and Pendle, while numbers remain high in Blackburn with Darwen, the Department of Health said, with local leaders setting up an "enhanced incident team" in an effort to bring infection rates under control.
Restrictions in affected areas will be reviewed again next week.
Meanwhile statistics from the Office for National Statistics said while recent figures had suggested the percentage of individuals testing positive for Covid-19 in households in England had risen slightly in July, the trend now appears to have levelled off.
Also on Friday Government scientists cautioned that transmission rates may be increasing.
The Government Office for Science and the Scientific Advisory Group for Emergencies (Sage), said the reproduction number, referred to as R, for the UK as a whole remains unchanged at between 0.8 to 1.
The growth rate – reflecting how quickly the number of infections is changing day by day – has changed slightly.
The Scientific Pandemic Influenza Group on Modelling (SPI-M), a subgroup of Sage, said: "We are starting to see early indications that these values may be increasing.
"This is not yet reflected in these estimates because the data used to calculate R and growth rate reflect the situation from a few weeks ago."
Earlier the Government announced it had reached agreements which it said will give British citizens early access to 90 million doses of two more potential Covid-19 vaccines.
The vaccines are being developed by US biotech company Novavax and pharmaceutical business Janssen, which is headquartered in Belgium and owned by Johnson & Johnson.
Under the in-principle agreements, the UK has secured 60 million doses of the Novavax vaccine, with it supporting a Phase 3 clinical trial with the National Institute for Health Research (NIHR).
Some 30 million doses have been secured from Janssen and ministers have agreed in principle to co-fund a global clinical study of its vaccine.
The new agreements, on top of earlier deals, mean the UK now has access to six different Covid-19 vaccine candidates in development, across four different types, representing some 340 million doses.
Despite the scale of the Government's potential stockpile, Kate Bingham, who chairs the Government's Vaccines Taskforce, warned it was still not known if any of the vaccines would be effective but said she was "reasonably confident" of one being found that will reduce the severity of virus symptoms and reduce deaths.
The Government's latest agreement follows 90 million doses in the pipeline under deals with an alliance between the pharmaceutical giants BioNtech and Pfizer, as well as the firm Valneva.
Some 100 million doses of vaccine could come from a vaccine being developed by Oxford University in partnership with AstraZeneca, while a deal has been struck for 60 million doses of GlaxoSmithKline (GSK) and Sanofi Pasteur's potential Covid-19 vaccine.
Business Secretary Alok Sharma said: "The Government's strategy to build a portfolio of promising vaccine candidates will ensure we have the best chance possible of finding one that works.
"Today's agreements will not only benefit people in the UK but will ensure fair and equitable access of a vaccine around the world, potentially protecting hundreds of millions of lives."
Alex Harris, the Wellcome Trust's head of global policy, said while he welcomed Mr Sharma's statement, it is "urgent" that the Government explains how it will ensure fair and equitable access to a vaccine.
The Janssen vaccine, which is being made available on a not-for-profit basis, is expected to begin the next phase of clinical trials later this year and will look at whether two doses can provide long-term protection from coronavirus.
Meanwhile, Novavax plans to make some of its vaccine at Fujifilm Diosynth Biotechnologies's facilities in Billingham, Stockton-on-Tees in the north-east of England one it is available.
The Government said if the Novavax and Janssen vaccines are proven safe and successful in clinical trials they could be delivered to the UK in mid-2021.
The vaccines would first be given to priority groups such as front-line health workers, those with serious diseases, the elderly and ethnic minorities.