Retailers are preparing for a shopping frenzy as Black Friday consumers buy their way to what is expected to be the UK's biggest day of spending.

Almost half of UK shoppers (47%) say they intend to buy a Black Friday deal, according to retail analysts Verdict.

Visa Europe predicts that £518 million will be spent on its cards today, making it the biggest day for e-commerce in UK history.

It estimates that online transactions will top 8.5 million today alone, up 22% on 2013.

However it also expects Black Friday to be followed by £500 million spent online on Monday, meaning the UK will shop its way to a £1.7 billion "cyber weekend" with a predicted record 31 million online transactions.

Visa Europe's managing director for the UK and Ireland, Kevin Jenkins, said: "Black Friday has become the UK's biggest online shopping day and we're forecasting £518 million to be spent this year. Following a jump last year, retailers are making a bigger Friday push this time around."

Although Amazon.co.uk introduced the UK to the event in 2010, local retailers have been quick to get involved. John Lewis has promised that its Never Knowingly Undersold commitment will remain in place subject to availability.

Amazon.co.uk said it predicted today's sales to eclipse the four million items sold on Black Friday last year.

John Lewis director of online Mark Lewis said the retailer expected to see traffic to its website between midnight and 8am today to be four times higher than any figures seen previously.

Let us know if you are hitting the stores to grab a bargain today. E-mail your pictures to newsdesk@southwalesargus.co.uk or tweet them to @southwalesargus

Among its deals are a half price Delonghi Prima Donna S Bean-to-Cup coffee machine, a half price Sage tea maker and an own-brand 49-inch television with £200 off.

Among Amazon's deals are a Citizen women's quartz watch with a saving of £140 and a Le Creuset cast iron skillet with £65 off, while ao.com is offering up to £300 off appliances such as televisions and fridge freezers and Currys PC World said it was ready for one order every second today and 1.6 million visitors to its website.

Asda said its Black Friday event would run for two days from 8am today, with "never before seen offers" on products ranging from mobile phones and tablets to computer games and toys.

Videogames retailer Game opened 316 stores at one minute to midnight for three hours, while doors are open today between 6am and midnight, predicting tens of thousands of customers will snap up bargains on consoles, games and accessories.

London's Westfield mall said it achieved its biggest shopping days of the year on the Black Friday weekend last year, and it expected record numbers this year.

But the shopworkers union Usdaw urged shoppers to "keep their cool" and respect those working the tills.

Usdaw general secretary John Hannett said: "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 shopworkers."