By Chris Page
BBC Radio Five Live Report
Underage drinkers are making use of websites which churn out false driving documents and proof-of-age cards for as little as £10 each, the BBC has found.
BBC researcher Elaine Hewitt was able to order a fake "driving permit"
A simple search reveals a huge number of websites selling "100% convincing" fake IDs "guaranteed to fool anyone".
The sites carry legal disclaimers stating the cards are "novelty" products, not copies of official IDs.
But youth workers told Radio Five Live Report they believe the cards are being marketed to underage drinkers.
Mike Davis, who owns a convenience store in Polzeath in Cornwall, seized 100 fake IDs in just six weeks during the school holidays.
"I tell parents I've taken a fake ID from their child and they don't know they're available on the internet," he said.
But the websites appear to be well known to many young people under the legal drinking age.
After midnight in Belfast City Centre, one 17 year old said he had spent several hours drinking in a bar after gaining admission with a fake student card.
Plenty of others said they had just turned 18, but had been getting into nightclubs and bars for several years.
In Liverpool, it was a similar story.
"What else are you supposed to do at that age?" said one teenage drinker who started using fake ID when he was 15.
In both cities, most late night venues seemed to examine ID rigorously.
But some clubs reportedly have a reputation as being an easy place for under-18s to have a drink.
Door staff at these venues do not seem to be inspecting ID closely, despite many of their customers looking as if they could have been under 18.
If licensed premises are caught serving under-18s, they face heavy penalties - including losing their licence and fines of up to £5,000.
The British Beer and Pub Association recommends that its members ask for ID if the customer looks 21 or under.
It says that the licensed trade is turning away a million young people a year for being underage or having no ID.
The online "vehicle card" looks nothing like a real driving licence
"In the vast majority of bars and clubs, it's impossible to get a drink if you're under 18," says Paul Smith, chief executive of the Bars, Entertainment and Dance Association.
Five Live Report ordered a fake "driving permit" online and showed it to Inspector David Connery, the head of crime prevention at the Police Service of Northern Ireland.
"It really worries me these fakes are out there," he said, pointing out anyone found using one faces getting a criminal record.
"The more discerning doorman will know it's false - but on a busy night it could easily fool people.
"If you are caught using a false ID getting into licensed premises you will be reported."
He also warns anyone "lending" their own genuine ID to underage drinkers could be charged with aiding and abetting an offence.
The BBC contacted several fake ID firms for an interview, but none responded.
The site which comes out on top when you search for fake ID through leading internet search engines carries a warning addressed to the press.
"We discourage the attempted use of our cards for the purposes of misrepresentation, both here and in the documentation supplied with our delivered fake ID products," it states.
But youth workers and publicans say they are in no doubt that the fake cards are marketed to underage drinkers.
They argue that the firms selling the cards are immoral and endangering people's licences and livelihoods.
Bill McComb, who runs several alcohol and drugs awareness programmes in Ballymurphy in West Belfast, says: "The companies know that young people are using these cards for an illegal purpose."
Five Live Report: The Faking Game will be broadcast at 1930 GMT on Sunday, 16 December. Or download the podcast from the Five Live Report website.