Shoppers rushed back to the High Street on Monday as non-essential retailers in England and Wales reopened after more than three months.
As of 5pm, High Street footfall had nearly doubled from a week earlier, as queues formed outside branches of Primark, JD Sports and TK Maxx and retailers extended their opening hours.
Beauty salons, barbers and pub gardens also reported a surge in bookings.
But it is unclear if the demand will last as shops try to recoup lost sales.
Shoppers began queuing at 7am at Primark shops in London's Oxford Street and Birmingham as the fashion retailer reopened 161 stores across the country.
Like others it is extending its open hours from 7am to 10pm to help prevent crowding in stores.
Primark boss Paul Marchant said: "We have been working really hard to get our stores ready to open safely; we are fully stocked with everything our customers have been waiting for.
"We ask our customers to continue supporting us and be mindful of our in-store measures, in particular if queuing outside and in-store."
There were also queues outside Selfridges in London and Birmingham, TK Maxx in Cardiff and JD Sports in Newcastle.
Amanda Philips, retail manager of the Moor shopping area in Sheffield, said it had been so busy it was like "an old fashioned Saturday in 2019".
"The sun is shining which always brings people out. We've been desperate to get outside and get a bit of retail therapy. The kids are still off school, it's half term," she told the BBC.
Hospitality venues, including restaurants, museums, theme parks and zoos, have also been welcoming people back, as well as gyms, swimming pools and spas.
At pubs such as the Oak Inn, in Coventry, drinkers queued up outside before midnight on Sunday to buy their first pints when outdoor service resumed.
Blink Brow Bar, a beauty salon chain with 21 outlets, said it had seen lots of "pent-up demand" ahead of Monday.
"We've had 1,000 clients on our waiting list from February. As soon as the appointments were up, we became fully-booked very quickly for the next few weeks," boss Vanita Parti told the BBC.
"That's a really exciting sign that people are so ready to step out of the house and indulge in a little self-care."
Julian Metcalf, chief executive of sushi chain Itsu, said he was hopeful demand would pick up as people returned to the High Street but said he felt "a bit nervous".
"It's scary," he told the BBC. "But there's a lot to be grateful for; the vaccination programme in our country is little short of remarkable, so there's no reason that we can't come back with real strength and positivity."
John Edgar, the boss of department store chain Fenwicks, warned cold weather in some parts of England and Wales could affect demand on Monday. He also said some shoppers would remain wary of heading back to the High Street for health reasons.
"It remains to be seen how many people choose to stay away in the short-term because of nervousness, but we believe that most retailers are offering a very safe environment to go shopping," he told the BBC.
The British Retail Consortium says businesses have spent hundreds of millions of pounds to make shops Covid-secure. Some, including John Lewis, will have "customer service hosts" to manage customer numbers, while Ikea has planned a staggered entry system and more frequent cleaning routines.
According to the latest figures from analyst Springboard, by 5pm footfall across all UK shopping destinations was up 146% from a week ago, and 481% higher compared with last year.
However, footfall was still 16.2% lower than the level seen on the comparable day in 2019, before the coronavirus pandemic.
Dr Gordon Fletcher, retail expert from the University of Salford, said: "When the shoppers return to the High Street there will invariably be a surge of foot traffic as the built up tensions of lockdown need to vented.
"The biggest risk for the old and new independent High Street retailers is that any surge will only be temporary as many shoppers quickly return to their increasingly refined ecommerce habits built up over the past 12 months."