Police have been involved in a massive operation to close down hundreds of illegal internet shopping sites, Sky News can confirm.
Over recent weeks, officers from the Metropolitan Police e-Crime Unit have been working to identify more than 1,200 scam websites, which claimed to offer designer goods, jewellery and electronic items.
In reality, customers either received nothing, or were sent counterfeit products.
It is thought many thousands of people may have been caught up in the scam, which is believed to have netted organised criminal networks millions of pounds.
The officer in charge of the operation, Detective Superintendent Charlie McMurdie, told Sky News: "Fraudsters target the victim's desire to buy designer goods at reduced prices, particularly at this time of year.
"The risk begins when your desire to purchase blinds your judgement or leads you to illegal websites. If it looks too good to be true, it probably is."
Victims also ran the risk of the criminals stealing their identity, credit card and banking details for misuse elsewhere.
All of the sites involved had UK domain names, but the vast majority of them were based in the Far East.
Detectives worked closely with the internet registry body Nominet, which is responsible for issuing UK domain names to more than seven million companies and organisations.
Lesley Cowley, chief executive, said: "We received clear instructions from the police to take down the .co.uk domain names, which have been under investigation for criminal activity.
"We worked closely with the police and our registrars to quickly carry out the instruction to shut down access to these sites.
"The vast majority of .co.uk domains are legitimate, but where there are investigations about improper or illegal activity, we work with law enforcement bodies such as the Metropolitan Police to help identify and then limit the number of illegal or fake websites."
Sky News has been told that Consumer Direct, Trading Standards, the Office of Fair Trading and many manufacturers also helped to identify the fraudulent web sites.
The operation concentrated on sites selling a number of designer items - including Ugg Australia Boots, GHD hair straighteners, and jewellery from Tiffany & Co and Links of London.
Because the vast majority of the sites were registered from Asia and mostly used false or misleading details, it made it almost impossible for victims to complain about poor quality, counterfeited items or goods not received.
It also made it difficult for Trading Standards or other law enforcement agencies to take action.
The operation is particularly pertinent now, as this time of year sees a massive increase in the number of people using internet shopping sites to purchase christmas gifts.
However, the many thousands already caught out by the scam websites have virtually no hope of getting their money back.
Commenting on the news, Consumer minister Kevin Brennan added: "Scam websites cost the UK consumer and the UK economy thousands of pounds each year.
"These sorts of website prey on consumers and, as you can see from the work of the Metropolitan police today, all agencies involved are working hard to make sure that this sort of con is stamped out.
"We already have 'scambusters' teams throughout the country and, as we announced earlier this year, we are planning to set up new internet enforcement teams to target online scams in order to protect consumers."