GSOH? Lonely heart liars will need one when they read this

Those who claim to be 30 and fit when they're 50 and fat will be publicly e-shamed

"Tall, sensitive, self-made millionaire, early 30s, seeks female for fun times and maybe romance." It sounds too good to be true - and for most women it actually is.

Online daters in Britain are rapidly losing their famous Good Sense Of Humour (GSOH) over the increasing number of would-be suitors fabricating personal profiles.

But there is good news for singletons: the dishonest online prowlers are about to get their comeuppance. A controversial US internet service, which unmasks "singles" guilty of lying about everything from their age and income to their marital status, is set to take off in Britain, where the dating industry is now worth an estimated £600m.

TrueDater.com, which was launched in California earlier this year, claims to attract hundreds of thousands of US visitors a month. And now its founders are making eyes at the British singles market.

The service, which provides feedback on users from a number of major dating sites, promises to end situations where personal profiles such as "40, sensitive, looking for TLC [tender loving care]" translates as "pushing 50, fat, looking for easy sex".

Visitors can post feedback on individuals registered on other sites. The system works in a similar way to user feedback on websites such as eBay, where a seller's character and history can influence whether a transaction is completed or not. Like eBay, the organisers of TrueDater insist the service is carefully monitored to ensure fair play.

"It's not just a review of a date; what you're doing is reporting whether this person was telling the truth - whether their online description was accurate," said Jamie Diamond, TrueDater's director of community relations. "A lot of people were saying they wished there was some kind of virtual best friend out there - and now there is."

According to the Economic and Social Research Council there are an estimated 11 million singles in Britain - a figure set to rise to 16 million by 2010 - with around one in five using a dating service.

But not everyone welcomes TrueDater. Lorraine Adams, director of a number of dating agencies including Gorgeous Networks and One Saturday, and credited with bringing speed dating to this country, warned that TrueDater would allow bitter former partners to attack the characters of their exes in public.

"This kind of service could promote a lot of back-biting and bitching," Ms Adams said. "I wouldn't consider associating it with any of my sites. If you've made a mistake with one person, why shouldn't you be forgiven for it?"

Darren Richards, chief executive and co-founder of DatingDirect.com, the UK's largest dating site, described TrueDater as "a novel idea", but said the vast majority of online daters were honest.

"There's no point in saying you look like Richard Gere if you look like Danny DeVito, because you're going to end up meeting people, so you're wasting your time and theirs," he said. "Most people realise that if you put your real self out there, there will be someone for you, but if you don't, you're never going to meet that person."

But there was support for TrueDater from Match.com, one of the world's biggest online agencies with 15 million members in 32 countries.

"This sounds like a positive thing," said Kevin Cornils, the European managing director. "It signals that people are getting more serious about online dating and are using it to find true relationships."

The idea was welcomed by internet dater Sean, 33, from Surrey. "Some people say their photo was taken two or three years ago, but I've seen photos that were taken two or three stone ago," said Sean, who was recently robbed by a woman he met on an internet site.

"One of the biggest things something like TrueDater would stop is scammers: people who aren't who they say they are, and some people who aren't even women."

'He was nothing like he claimed to be'

Claire Nicholson, 34, a life coach from west London, went on a disastrous lunch date earlier this year with a man she met on a singles website.

"I was expecting a tall, dark, handsome, sophisticated man in his late thirties, but as he walked towards me I could see he looked nothing like his picture. It had to be at least 10 years out of date," Ms Nicholson said. "And it wasn't just that he was much older than he had said: he was haggard, he looked like he had slept in his clothes, and his hair was lank and greasy."

Ms Nicholson's date took her to a dilapidated local pub for lunch, before informing her that the main courses were too big and expensive, and she had to order from the £5 section.

"As lunch arrived, he bent his head down to start eating, and it was then that I noticed the dandruff - it was the size of hailstones and utterly disgusting," she remembered. "I kept thinking it was going to fall into his food, and had trouble digesting mine."

To compound his failings, Ms Nicholson's admirer broke the golden rule of dating, and began talking about his ex.

"He opened his wallet and pulled out a tiny bit of paper with a long Latin name on it, which he told me was the name of an STD his ex-girlfriend claimed she may have given him," she said. "I couldn't believe it."

VIRTUAL...

'Stand out in a crowd; 36-40; down to earth, very direct and disgustingly and childishly funny; a river of kindness to my friends... Photos are for a glossy mag shoot. I've cut the hair since'

REALITY...

'Might have stood out in a crowd, but for all the wrong reasons; looked at least 10 years older; a "river of kindness" as long as it cost £5 and came with chips. Photos so old that he looked about 20 in one of them'

'He started talking about sex very quickly'

"He sounded like a really decent, well-mannered bloke," said Phillipa Le Grys, 26, from north London. "We met for a drink in Covent Garden. I decided I didn't fancy him after 10 minutes. He was a real geezer, just wanted to discuss football and started talking about sex very quickly." Ms Le Grys then realised her coat had been stolen - along with her phone and car keys. They went to the police station together, then the man jumped in a cab and left her shivering by the roadside.

VIRTUAL...

'Company director; only drink occasionally; don't use drugs; into extreme skiing; muscular body'

REALITY...

'He was a complete beer monster who wouldn't shut up about Chelsea FC. He worked in sales'