Fights have broken out and the police have had to be called after customers queued all night and shoppers overran supermarkets as Black Friday hit the UK.

Officers were called to at least four supermarkets in London alone as shoppers surged into stores. Police were also called to incidents in Manchester, Cardiff and Glasgow.

John Hannett, from the shop workers' union USDAW, warned: "Black Friday can be very difficult for staff. With overcrowded shops and highly excited customers, sometimes tempers flare and things can get out of control.

"Retail staff are keen to give great customer service and are trained to provide a good shopping experience, but that can be difficult if people are angry and aggressive.
"So my message to the shopping public is clear. Enjoy Black Friday, I hope you get what you're looking for and at a great price, but please keep your cool and respect shop workers."