Crowds of bargain hunters rush into a department store on Boxing Day
Thousands of shoppers have flooded into UK stores hoping to pick up bargains in the traditional Boxing Day sales.
There were queues outside major stores and many shopping centres reported an "excellent" start to business.
Experts predicted a sales boost because 26 December was a Saturday and people would buy goods before the VAT rate returns to 17.5% next week.
At Selfridges in Manchester a few shoppers were hurt when a panel from a plastic ceiling light fell onto them.
The happened in the ground floor accessories area just after the store opened at 0800 GMT. Four people suffered cuts to their heads and bruising.
Adam Caulfield, from Oldham, said: "It was bedlam. Two or three girls had loads of blood gushing from their heads. There was at least 400 or 500 people just in that section."
Joe Lynam, BBC News
Such had been the sense of impending doom among Britain's retailers 12 months ago that last year's Boxing Day sales ended up being a mere continuation of the massive discounting which had been under way for most of last December.
This year there is enough evidence to suggest that those retailers who have survived the recession have refused so far to blink in their annual game of chicken with their customers.
But that blinking will begin in earnest today when tens of thousands are expected to take to the High Streets and out of town centres to pick up the kind of bargains unimaginable two days ago.
Clarks, Next, Matalan and IKEA are all offering up to 50% off today - with Debenhams cutting prices by up to 70%.
Then there's added the impetus of VAT rates going back up to 17.5% on New Years Day. That should persuade many shoppers of big-ticket items such as furniture and white goods to bring forward their trips to town.
In a statement, the store said it immediately cordoned off the area and that paramedics arrived within five minutes."Selfridges is currently assessing the cause of the incident," it added.
Discounts this year were not expected to be as great as last year because firms had been more cautious about stock levels.
Last year, Boxing Day footfall at shops nationwide was up 12.5% on the previous year, driven by discounts as large as 90% in some stores.
Retailers offered the huge reductions in order to clear excess stock left behind in the wake of the financial crisis.
However, Capital Shopping Centres (CSC), which owns 14 UK shopping sites including St David's in Cardiff and Westgate in Oxford, said its Braehead centre in Glasgow was busier than last year.
And it said the Metrocentre in Gateshead had seen an "excellent" start to the sales.
CSC commercial director Trevor Pereira said laptops, TVs, mobile phones and home-wares were in high demand, along with winter clothes and cocktail dresses.
"Shoppers have been planning their sale purchases before the VAT hike comes into effect, and as a consequence we are extremely busy," he said.
The government cut the rate to 15% in December last year in a bid to boost the struggling UK economy.
Staff at Lakeside shopping centre in Essex said drivers arrived as early as 0500 GMT to get to its branch of Next, which opened an hour later.
General manager Paul Lancaster said it had been "an excellent day".
More than 125,000 shoppers were expected at Bluewater Shopping Centre in Kent, where general manager Andrew Parkinson said car parks were 70% full by 1100 GMT.
Similarly, the 12,000 space car-park at Sheffield's giant Meadowhall shopping centre was virtually full by that time.
The Bullring in Birmingham is expecting 200,000 shoppers on Boxing Day, 150,000 on Sunday, and another 200,000 on each of the following two days.
Retailers in London's West End are expecting a total of £60m to be spent by 500,000 shoppers.
Jace Tyrrell from the New West End Company said: "Boxing Day is the single biggest day of the January sales in the West End but we're expecting a total of 1.2 million shoppers spending around £120m over the next three days."
Selfridges on Oxford Street reported its most successful start to a Boxing Day's trading.
The department store said business was up 10% on last year across its four stores in England.
Tesco anticipated it would have 1.4 million people passing through its doors, with electrical and entertainment products proving popular. Bananas were flying off the shelves at 625 per minute.
Jonathan de Mello, from market data company Experian, said most retailers made around 25% of their weekly revenues on a Saturday.
"It is conceivable that Boxing Day 2009 could be 'Super Saturday' - the biggest shopping day of the year so far - rivalling even 23 and 24 December," he said.
Research by American Express suggested more than £3bn would be spent in the sales, with more than a third of those questioned saying they were more likely to spend because of the impending VAT increase.
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