Black Friday discounts and bad weather have been blamed for a decline in Boxing Day shoppers, with retail analysts reporting a fall in the number of people heading for the sales.
Springboard, which analyses customer activity in stores, said footfall had seen the largest decline since 2011, dropping by 8.6%.
It said Boxing Day was becoming less important as a trading day.
But there were still queues for some shops from as early as 04:30 GMT.
However, the retail data analyst, which examines information from UK High Street and shopping centre cameras, said more people were waiting until later in the day to head to the shops in search of a bargain.
Diane Wehrle, insights director at Springboard, said: "It is clear that consumers visited high streets more in the early evening than during the day."
By lunchtime on Boxing Day, footfall was 10.6% lower than last year, its biggest annual decline since 2010, when Springboard first published its data.
Commenting on the disappointing morning for retailers, Ms Wehrle said many consumers were still celebrating Christmas with their family on Boxing Day, while the rainy weather, online shopping and increased Black Friday spending were also possible factors for the drop in footfall.
"Boxing Day is indisputably a less important trading day than it once was," Ms Wehrle said.
Some bargain-hunters did brave the rain, with some shoppers on London's Oxford Street waiting for stores to open at 9am.
Others queued outside Selfridges in Greater Manchester's Trafford Centre at 4.30am.
As the doors to Next opened in Liverpool at 06:00 GMT, more than 150 people were waiting outside the store.
A total of £3.7 billion was expected to be spent in the Boxing Day sales, according to Barclaycard, with four in 10 UK adults predicted to spend an average of £186 each.
But environmental concerns were also expected to drive down buying, with shoppers also predicted to spend £200 million less in post-Christmas sales this year compared to last year.
Opinium Research surveyed 2,002 UK adults online for Barclaycard between 29 November and 3 December.