Retailers are in for a windfall from the "Eid effect" as big-spending Middle Eastern consumers travel to the UK after Ramadan.
Payments specialist Worldpay said its transaction data shows that Middle Eastern consumers raise their spending by a quarter as Eid dawns at the end of Ramadan, which breaks a month of fasting and is one of the most important events in the Islamic calendar.
And they outspend other nationalities when they travel to the UK for its variety of shopping destinations, like London's West End.
Worldpay said consumers from the Middle East spent an average £152.40 per transaction in August 2013, while Europeans spent just £49.00 and US visitors to the UK £65.41.
"Britain has some of the best shopping in the world and retailers need to wake up to the fact that the biggest spenders all come from abroad," said Dave Hobday, managing director at Worldpay UK.
"There's a Middle Eastern gold rush underway and millions of pounds are at stake as tourists from Qatar, Saudi Arabia and the UAE flock to the UK to outshop and outspend the rest.
"The pressure's on for UK retailers and it's not enough just to deliver great service and hope for the best. Winning retailers must work harder than ever to make Middle Eastern shoppers welcome.
"High-end retailers and boutiques are now employing multi-lingual staff and giving shoppers the option to pay by card in their own currency. We're on the eve of Eid and this spending frenzy is a gift retailers just can't afford to miss."