Millions of shoppers have been seeking out bargains across the UK as the post-Christmas sales hit top gear.
Retailers know the next few days are crucial
Many shops opened their doors for the first time since Christmas Eve, on what is traditionally one of the busiest days of the shopping year.
Analysts say the next few days may be crucial as High Street conditions have been tough and holiday trade can make up half of some firms' annual profits.
The number of people shopping on Boxing Day was well up on 2005, figures show.
According to retail analysts Footfall, the number of shoppers visiting top stores across the UK on Tuesday was up 7% on last year.
Selfridges reported first-day sales 14% higher than a year ago while the Trafford Centre near Manchester saw sales 3% up on last year.
But this rush of activity may not translate into higher sales across the High Street, particularly with pressure from supermarkets and internet stores already leading to discounting.
Nottingham's Victoria Centre and south Gloucestershire's Cribbs Causeway were among the shopping centres to open early on Wednesday to allow people to take advantage of clothing chain Next's sale, which started at 0500 GMT.
More than 1,000 people queued into the early morning ahead of the Manchester Arndale Centre's opening at 0300 GMT.
Brent Cross Shopping Centre in North London was expecting 150,000 shoppers on what it said would be its busiest day of the year - a day which started with long queues and heavy security to stop queue-jumpers.
"We have had a very good start," said Brent Cross spokesman Tom Nathan, who added that it had enjoyed a strong run-up to Christmas after a slow start to the festive period.
"They are happy with their performance," he said of retailers' verdicts on the important pre-Christmas period.
"It has not been fantastic but good enough to be happy."
John Lewis says it is encouraged by how the sales have started
John Lewis reported brisk business on the first full day of sales, with queues at its flagship store on Oxford Street and other outlets.
"There is a nice momentum building up in the branch," said a spokeswoman.
Queues formed at several of Marks & Spencer's largest branches well before they opened at 0800 GMT.
The retailer said its stores had been "very busy", reporting strong demand for men's suits, women's coats and lingerie which were all heavily discounted.
Shoppers are expected to spend more than £30bn over the festive season, slightly more than last year.
But there have been predictions of falling profits in some sectors, with the discount market expected to come under most pressure.
But, encouragingly, John Lewis said sales rose 16% in the week to December 24, boosted by the cold weather and a surge of last-minute buying.
Tim Sleep, retail director at the consultants Ernst & Young, said there was "intense" competition among retailers.
"Now, more and more you're seeing signs such as 'Winter Sale' or 'Seasonal Sales' instead of the post-Christmas or January sales," he said.
"The last two or three years we've seen more and more pre-Christmas discounting.
"But it's a tactic, along with many others, that retailers are using to employ to drive customers through their doors."