The logo for The Stand, which features a painting child in a cowboy hat pointing a toy gun at his head, was deemed to be unsuitable after Virgin Trains raised concerns it could promote gun crime.

Tommy Sheppard, the director of The Stand, has written directly to Sir Richard asking him to overturn the ban. In the letter, he said the rail company's decision was "as ridiculous as it was insulting".

Mr Sheppard said the York Place club, Scotland's largest comedy club, had been pursued by marketing managers for weeks to place an advert in the official Virgin Trains magazine, Hotline. The magazine is available to passengers on Virgin Trains across the country, including several routes in and out of Edinburgh.

Eventually The Stand agreed to place an advert, and sent over the proposed section featuring its well-known logo for approval.

The next day however staff were contacted by Ink, the company which publishes the magazine, and told that the advert could not be used, because of concerns about gun crime.

Mr Sheppard said the logo, which has been used by the club for more than ten years, was "a metaphor for stand-up comedy" and said whoever banned it was an "overzealous self-appointed arbiter of taste and decency".

He said "I was really surprised to be told that they wouldn't run the advert, and I think it is crazy."

"To suggest that this image in some way condones or promotes gun crime is just nonsense, and I hope that Sir Richard will be able to see that this is just a silly mistake.

"We were speaking to their advertising people for weeks before we finally agreed to put in an advert, so it was quite incredible that they then turned around and said it was unsuitable."

In his letter, Mr Sheppard also said the club had "advertised extensively without any problem", on services run by First ScotRail and Citylink.

Last year, however, the logo was also banned by Lothian Buses from appearing in one of its promotional pamphlets, after the bus company decided it was inappropriate.

A spokesman for Virgin Trains said: "Hotline is a magazine that is available to all passengers on our trains and we are greatly concerned about carrying anything that promotes illegal knife or gun crime, and so for that reason we have deemed this image unusable. We are more than happy to discuss alternatives with the Stand Comedy Club."