Publicity shots for the shirt deal went ahead anyway

Police are now searching for Stephen Venney, 49, who went missing on 1 May - the day he was due to take part in a news conference announcing the shirt sponsorship deal with Grimsby Town.

In 1996, Mr Venney was jailed for 20 months for swindling thousands of pounds from a Conservative club in Immingham, near Grimsby, where he held the post of treasurer. The club was forced to close with heavy debts.

Jarvis has admitted that Mr Venney set up the three-year deal with the struggling football club, which has just been relegated to the Second Division, despite being "only at middle management level".

Resignation

Mr Venney was hired in March 1999 and became a management accountant at Jarvis Rail, the contractor responsible for maintaining the stretch of track where the Potters Bar rail tragedy happened a year ago.

"We were not aware of his previous convictions when he joined us," a Jarvis spokesman told BBC News Online.

"Clearly we are interested in finding out how a man with a fraud conviction could end up on our payroll."

This deal is a life-saver for the club - it is one of the biggest income streams the club has Tony Richardson, Grimsby Town commercial manager

He said the sponsorship deal would go ahead despite the revelations.

A Humberside Police spokesman said that since his disappearance, Mr Venney had written letters postmarked in Plymouth, Devon, to his family near York and to Jarvis, offering his resignation.

"But we don't know where he is and we're very concerned for his safety. He is not facing any charges and our interest is purely in trying to find a missing person," said the police spokesman.

Jarvis has accepted Mr Venney's resignation.

Grimsby Town FC commercial manager Tony Richardson said: "This deal is a life-saver for the club.

"It is one of the biggest income streams the club has and I never thought I would be signing a deal like this at Grimsby Town.

"It is a First Division sponsorship package and that is where we want to be."