IT is the biggest shopping day on American calendars, but has become infamous for scenes of manic bargain-hunters grappling and fighting in the aisles as they scramble for discounted goods.

And now the Black Friday phenomenon has well and truly crossed the Atlantic, with Scottish supermarkets closing their doors last week when scuffles broke out over marked-down TVs, computers and other everyday goods.

Witnesses described how bargain-hunters behaved "like animals" and likened scenes to a war zone on Friday as tempers flared at the tills in Glasgow and Dundee, where police were eventually summoned to prevent the bad behaviour from spilling over into violence.

It is likely that such scenes will be repeated for years to come, as the event is now firmly entrenched in retailers' plans and shoppers' expectations.

Black Friday traditionally falls on the day after Thanksgiving and, for many American retailers, it signifies the start of Christmas shopping and festive profits.

In the past, smaller retailers would mark it as the day when their accountants would write up profits, taking them out of the red and into the black. As a result, the term Black Friday was first recorded in 1966 in Philadelphia.

But now it has joined "trick or treat" and "prom night" in the ­Scottish consciousness - its popularity spurred on by the internet and the power of social media.

Retailers in the UK opened at midnight to maximise ­shopping times and put deals online ­overnight, but many seem not to have expected the surging crowds that quickly overwhelmed staff's attempts to hold them back.

Across the UK, stores were forced to close and the day ended with at least three people arrested and a woman hurt after being hit by a ­falling television.

Tesco at Silverburn in Glasgow was closed after people clashed over discounted goods, while police were called to a Tesco Extra store in Kingsway West, Dundee where staff made the decision to shut the shop.

Scottish digital consultant ­Stewart Kirkpatrick said it was almost inevitable that shops on this side of the pond would start to hold Black Friday sales despite Thanksgiving having little or no cultural meaning here. Growing US influence on UK culture and prominent sales on the internet mean the event is now inescapable for many Scots.

He said: "Black Friday is a US thing that has developed a huge presence on Twitter because of the amount of people who use the site over there. Nasa was tweeting #BlackholeFriday to drum up interest, which gives an indication of the term's presence in the public consciousness.

"Social media will have raised the profile of the term among the British public and shops have been very successfully cashing in on that.

"But it remains to be seen if it will be remembered as a name for sales or as a spectacle. A lot of the videos being posted and tweeted are of punch-ups and heaving crowds, so it may be that the term will come to mean crowded shops rather than bargains."

Other stores hit by Black Friday chaos included Tesco stores in Edmonton, Willesden and Surrey Quays in London.

Images posted online showed chaotic scenes, with witnesses describing "mayhem" as discounted coffee machines went on sale.

Footage from a London Asda - owned by the US giant Walmart - of a woman clinging to a TV as shoppers tried to drag it off went viral, one of many videos of bad behaviour that surfaced on social media.

Some users on Twitter reacted with disgust to the scenes, with one tweeting :"It's Black Friday - that means don't stop shopping til they decline your card or you pass out from exhaustion."

Customer Louis Jones added: "Can't believe all these idiots fighting over televisions, sort it out Tesco," while Darren Brade said: "I guess the UK is truly the 51st State of America."

Leigh Sparks, professor of retail studies at Stirling University, agreed Black Friday was here to stay. He said: "The internet has had a lot to do with the popularisation of Black Friday in the UK as it began on Amazon around four years ago, while it is also part of the Americanisation of culture in general.

"We are very aware of what happens in the States, especially what happens online, and people will have seen those deals taking place over there."

He added: "As a retailer, you are very much looking for an event because they are very good at bringing on sales. So it's easy to understand why they have been keen to bring in Black Friday sales. Sales get people in the door and make them aware of your shop. Black Friday is also very useful for firing the starting gun for Christmas."

A spokesman for Tesco said the decision to start Black Friday sales was taken due to customer demand. He said: "We ran a Black Friday sale last year and have kept that up for our sites this year. Black Friday sales have happened in other shops for around five years now."

A spokeswoman for Asda said: "We do not condone the behaviour of a very small number of people in our Wembley store this morning. Despite our extensive planning and additional security colleagues, there was an isolated incident when the store opened. The sale has run smoothly in all our other 440 participating stores."