Running into trouble: the directory inquiry firm that caricatured top athlete

The marketing campaign for the 118 118 directory inquiry service featuring two replicas of the 1970s athlete David Bedford - complete with droopy moustaches - broke advertising guidelines, media watchdogs ruled yesterday.

In a decision with implications for the protection of the image of sports stars and celebrities, Ofcom said the adverts were in breach of the Advertising Standards Code because they caricatured Mr Bedford in a "comically exaggerated" manner.

The ruling clears the way for Mr Bedford, 54, a former 10,000 metres world record holder and now race director of the London Marathon, to continue with his legal action for damages against The Number, the company that runs the 118 118 service. But The Number has not been banned from using the image in the future. Ofcom said its decision was punishment enough and banning the adverts would be "disproportionate."

Although The Number said this allowed them to continue using the image, Mr Bedford interpreted the ruling otherwise, saying "no new adverts using the mystery runners can be shown in the future without further breaches of the code".

He said: "I am pleased that Ofcom has now vindicated my claim that The Number has 'ripped off' my image. The Number had denied this all along. It's a pity that The Number didn't think to ask me for my approval at any point during what has turned out to be a long campaign."

Mr Bedford had appeared to endorse the idea last year before the campaign began and was happy to be photographed with his two doppelgangers, saying it was "a bit of fun".

Giving judgement in an appeal by The Number against a ruling by the now defunct Independent Television Commission, Ofcom said that was not relevant as a defence because Mr Bedford had not seen the ads at that point. The Number also claimed the characters in its advertisements were based on numerous runners from the Seventies, including the American athlete Steve Prefontaine, who is now dead.

Ofcom decided that the advertisements "do caricature David Bedford by way of a comically, exaggerated representation of him looking like he did in the 1970s, sporting a hairstyle and facial hair like his at the time, and wearing running kit almost identical to the running kit that was distinctively worn by him at the time".

It conceded the caricature was "not fortuitous" to Mr Bedford but decided he "had not necessarily suffered actual financial harm as a result".

Mr Bedford's legal case has been strengthened by last year's court ruling that the radio station TalkSport manipulated an image of the Formula One driver Eddie Irvine in an advert to make it appear as if he was listening to the station. The judge in that case said that there was a commercial value to the endorsement to Irvine and that it was a right he could protect.

Lawyers say Mr Bedford - who unlike Mr Irvine is largely out of the public eye and does not regularly endorse products - may still have to prove that the adverts suggested he was endorsing the 118 118 service and that he had lost out financially.