There were scenes of chaos after stores in Northern Ireland slashed prices for Black Friday.
Impatient shoppers keen to grab a limited number of bargains queued from early morning before jostling each other for half-price electrical goods.
One video clip taken by a bargain-hunter at Tesco in Craigavon showed men and women pushing, shoving and even wrestling each other for televisions as outnumbered staff tried to calm the situation.
Police officers were photographed patrolling at the scene, although a spokesman for the PSNI said no crimes were reported.
Other footage filmed at supermarkets elsewhere in Northern Ireland showed hundreds of people in similarly frantic scenes that were replicated across the UK.
Greater Manchester Police attended seven Tesco stores and three men were arrested.
Police were also called to various Black Friday sales in Dundee, Glasgow, Cardiff and London.
A spokesman for Tesco said: "We always take guidance from police authorities on security measures in stores and we'll work closely with them to make any improvements for next year."
Asda said more than two million customers had visited its stores across the UK yesterday morning, with some queues starting at 3am.
It sold 8,000-plus TVs in an hour and 10,000 tablet computers in just two hours.
Asda is continuing the Black Friday event this morning, with some stores opening at 8am.
Black Friday has historically been a major sales day in the United States but has become popular in the UK, coinciding with many consumers receiving their last pay packet before Christmas.
Traditionally it is the biggest day for online shopping in the UK with an expected 31 million transactions.
Deals on offer included a Polaroid 32in TV down from £179 to £89 (a saving of 50%) and Skylanders Trap Team Starter Pack for X Box, Wii and PlayStation reduced from £54.99 to £29 (a saving of 47%).
However, many shoppers in Belfast felt the sales bonanza had been overhyped.
Marie Bingham from the city was shopping with her teenage son.
She said she usually did her shopping online as she preferred that to facing the crowds.
"Town has been mad; I always do my shopping online and I would definitely stick to that after seeing the crowds out," she said.
Others left underwhelmed by the Black Friday offering in Belfast city centre yesterday afternoon included Arlene Megaw and her daughter Yasmine.
They came to look for some bargains but were disappointed.
Ballykelly sisters Mairead McVeigh, Anne Doherty and Sheila Duffy were making a long weekend of the Black Friday sales.
"We are all down without the men, we do this every year before Christmas," said Mairead.
"But we thought there would have been more money-off stuff," they said.
Black Friday is the day after Thanksgiving in the United States, often regarded as the beginning of the Christmas shopping season. The name originated in Philadelphia, where it was used to describe the heavy traffic that would occur on the day after Thanksgiving. Also "Black Friday" indicates the point at which retailers begin to turn a profit, or go "in the black".