BROADCASTING minister Janet Anderson today called for TV companies to tighten up vetting procedures after a Burnley contestant on Channel 4's Fifteen-to-One quiz was exposed as a convicted sex offender.

TV company bosses were today still deciding whether to pull the plug on the quiz heat won by the 42-year-old, a former teacher at an East Lancashire school, and the already-recorded finals of the popular tea-time show.

The Lancashire Evening Telegraph revealed yesterday that the man, who cannot be named following a judge's ruling, was convicted at Preston Crown Court in 1994 of four sex assaults on girl pupils and jailed for two years.

The alert was raised by local viewers who heard he had taken part in Fifteen-to-One recordings and Channel Four admitted it did not ask contestants whether they had criminal convictions.

Today a company spokesman said they were reviewing the whole situation and were in talks with their lawyers.

But Mrs Anderson, MP for Rossendale and Darwen, said she would be taking the issue up with broadcasters.

"It is very disturbing indeed that a convicted sex offender could have appeared on a quiz show in this way.

"It's very important indeed that broadcasters do their utmost when considering people to appear on such programmes to ensure they are properly vetted. "I shall be speaking to broadcasters about this issue."

Burnley MP Peter Pike said: "I'm very concerned about this.

"Programme makers must be much more careful to make sure contestants do not have criminal convictions, particularly those involving children.

"This is a very difficult area. But obviously we don't want people convicted of offences against children appearing in these shows and producers must take whatever steps are considered appropriate to prevent them doing so."

Other broadcasters were today keen to point out that they do have vetting systems for quiz and game-show contestants.

A spokesman for Cellador, makers of Britain's most popular quiz show "Who wants to be a millionaire?" said: "We always do everything to ensure our contestants do not have criminal convictions. We even check right down to driving offences -- we are very vigilant."

A spokesman for Family Fortunes makers Carlton TV, said selection was carried out by very experienced staff and it would soon become apparent in interview if someone had a serious criminal conviction.

The BBC, whose shows include the popular The Weakest Link quiz and The Generation Game, said its guidelines to producers were quite clear on the issue.

They state: "Steps should be taken to screen out contestants who are clearly unsuitable such as those who have been convicted of very serious offences."