A vast security operation is under way to protect hundreds of Spring Bank Holiday events across Britain this weekend as counter-terror detectives continue to question nine men over the Manchester bombing.
More than 1,000 armed police are on standby as major spectacles, including the FA Cup Final at Wembley and the Aviva Premiership Rugby Final at Twickenham on Saturday, are expected to draw tens of thousands of people into public spaces.
On Sunday the Great Manchester Run will go ahead as planned, with defiant runners and spectators due to turn out in large numbers as the city recovers from the atrocity.
Despite the country being placed on critical alert, police have urged people to go out and enjoy themselves.
The country's leading counter-terror officer said "immense" progress had been made in the probe into a suspected network linked to suicide bomber Salman Abedi.
Nine suspects, the youngest an 18-year-old man, are in custody following days of intense police activity that saw 11 people detained in a series of raids in Greater Manchester, Warwickshire and Merseyside.
The latest arrest, of a 44-year-old man in the Rusholme area of Manchester, took place on Friday evening, Greater Manchester Police (GMP) said.
The arrest occurred as witnesses reported seeing armed police storm a number 41 bus on its way to the town centre at around 7pm.
A shopkeeper said he hid up to six terrified passengers in the back of his Spar store on Oxford Road while armed police and uniformed officers attended the scene.
Investigators are searching 12 locations across the North West, with activity expected to go on throughout the weekend.
Twenty-two people, including seven children, were killed and scores injured when Abedi launched a suicide attack at Manchester Arena following a pop concert on Monday night.
The blast occurred minutes after US singer Ariana Grande left the stage and her fans, many of them young girls, filed out of the venue.
On Friday the star vowed to return to the city where her fans were targeted, promising she would hold a benefit concert to raise money for the victims and their families.
She also urged fans to donate to Manchester Evening News's fundraising appeal, which has raised more than £5 million.
Grande, 23, said: "Our response to this violence must be to come closer together, to help each other, to love more, to sing louder and to live more kindly and generously than we did before.
"We will not quit or operate in fear. We won't let this divide us. We won't let hate win."
The massacre was the worst terrorist atrocity to hit Britain since the July 7 attacks in London in 2005.
On Tuesday the terror threat level was raised to critical, meaning an attack may be imminent, for the first time in a decade.
The Prime Minister also sanctioned Operation Temperer, allowing the military to be deployed to protect key sites, and the Changing of the Guard at Buckingham Palace was cancelled.
The ceremony resumed on Friday as Metropolitan Police Assistant Commissioner Mark Rowley, the national lead for counter-terror policing, urged Britons to go about their business as usual over the weekend.
He said police arrested some "key players" and made significant "finds" as they raced to dismantle a network linked to Abedi, 22.
He said: "Enjoy yourselves and be reassured by the greater policing presence you will see.
"We can't let the terrorists win by dissuading us from going about our normal business."