Some of the UK's biggest retailers will cash in on a US tradition this Friday, as they slash their prices ahead of Christmas.
In the US, thousands of stores discount their prices the day after Thanksgiving, and many open for longer hours.
Last year a record number of shoppers visited stores over the Black Friday weekend, spending a total of $52bn (£32.6bn) - an average of $398 (£249) each, according to the National Retail Federation.
US online retailer Amazon was one of the first companies to bring the trend to the UK.
It launched a week-long Black Friday sale on Monday, which it claims "offers millions of pounds of savings on hundreds of Christmas gifts".
"There are more retailers launching sales this year than ever before - and many British consumers are becoming aware of tradition for the first time," Retail Week's Gemma Goldfingle told Sky News.
"In the US it an absolute phenomenon, with people queuing up all night to snap up the best deals.
"It has not reached that level here and whether it ever will is another matter."
"A lot of British retailers would prefer not to have it," she said.
"They want to be selling items at full price ahead of Christmas, especially given the tough economic conditions."
Black Friday, which is thought to refer to the first day of the year that retailers go "into the black", comes just ahead of Cyber Monday - which the marketing industry claims is the busiest day in the online shopping calendar.
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