The chances of winning can be as little as 1 in 5,000.

The booming industry in premium rate quiz channels and late-night programmes has generated 100 million calls over three years.

But the Culture, Media and Sport Select Committee was told that some producers had manipulated participants to maximise the number of people being charged the 75p connection fee.

Detectives in the City of London Police economic crime department are investigating allegations made against one company, Big Game TV!, by You and Yours, the Radio 4 consumer programme.

Operators of another company, Quiz Call, admitted to the committee that, on one occasion, contestants were prevented from being put through for up to 40 minutes to prolong the game. Players were encouraged to keep calling back to answer an easy question, paying the 75p connection fee each time.

Ostrich Media, Quiz Call’s owner, said that the producer responsible no longer worked for the company. Blocking calls was “unacceptable behaviour” and not company policy.

Paul Farrelly, the Newcastle-under-Lyme MP, said: “This is not just trash TV. It is tantamount to theft and fraud.”

Shari Vahl, a You and Yours presenter, said: “If you are misled about how much you need to spend to get through the door it could be a scam. It is fraud if no one gets through for 30 minutes.”

The Mint, running nightly on ITV1 from midnight to 4am, is the most popular call-in show.

Jeff Henry, the director of ITV’s consumer division, said that it received 100,000 calls an hour, and, at peak time, 6,000 calls a minute. But only one call is selected for connection every 85 seconds at random by computer. Nigel Evans, the MP for Ribble Valley, asked Mr Henry why a message was not put on screen, warning viewers that they had “about a 1 in 5,000 chance of winning”.

Mr Henry said: “At any time that a person calls that information would literally be out of date so we could be accused of misleading viewers.”

Mr Henry said he thought that a 1 in 5,000 chance of winning a possible jackpot of £135,000 was a fair offering. ITV tells participants that they cannot play on after reaching a call limit. But they are charged 75p for each call made after reaching the limit.

Mr Farrelly asked: “Have you taken any legal advice as to whether that constitutes theft?” Mr Henry replied: “We do not believe it constitutes theft.”

Quizzes produced £29 million for ITV in the first half of 2006, of which £9 million was profit, Mr Henry said.

Ofcom, the media regulator, said that the shows were the fastest-rising complaint source, with 800 this year.

Shaun Woodward, the Creative Industries Minister, told the committee: “If they turn out to be scams they are illegal and there are already severe penalties.”

Mr Woodward said that he had tried to play a number of games, including The Mint and Quiz Call. Although he had been put through to the presenter on one occasion, he had not been successful on any of them.

After the hearing, John Whittingdale, the committee chairman, said that he expected Michael Grade, the new head of ITV, to take a close look at its call-in quiz operations.

The committee will publish recommendations for new regulations after Christmas.

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