By Ben Geoghegan BBC News

Not a stumper

The new Gambling Commission has already expressed concern about one activity in particular - the use of premium phone lines to take part in TV, internet and mobile phone quizzes.

Televisions, cars, holidays in the sun - the chance of a prize is just a phone call away. And with questions as simple as "What are Cumberland, frankfurter and pepperoni all types of?" it's easy to feel you could be a winner.

Thousands of callers join in competitions like this every day. Phone-in quizzes on TV, websites and mobile phones are becoming more and more popular.

Of course, it's all just a bit of fun, but some groups worry about callers being landed with huge bills.

Rosemary McCulloch, of the Voice of the Listener and Viewer, says that for some of the most vulnerable members of society, it could become an addiction.

"It's a form of gambling, it can turn out that way and it could be the beginning of a slippery slope," she says.

Major overhaul for gambling laws

This kind of TV is becoming more and more popular. Twelve new channels dedicated to brain teasers and quizzes have been set up in under a year.

But complaints have gone up as well - 150 in the past three months. Players say the rules aren't clear, and eight investigations are now under way.

George Kidd, the director of ICSTIS, which regulates premium phone lines, says one risk is compulsive use, with people racking up large bills for these services.

"A second risk, if they're not run responsibly, is people losing trust in the channel, in the satellite structure, and in the premium rate payment mechanisms."

The BBC also sometimes uses premium lines, but its guidelines mean they cannot be used to make a profit.

Too easy

Another criticism of these quizzes is that there is no real test of general knowledge or intelligence - the questions are so easy that just about everyone can get them right and everyone has an equal chance of winning.

Win a holiday!

In that sense, there is no competition at all, it is more like a lottery. The problem is that lotteries are supposed to raise money for good causes.

"The essence of the problem is that a lot of these so-called prize competitions are in effect lotteries," says Tom Kavanagh, the deputy chief executive of the Gambling Commission.

"In a legal lottery, at least 20% of the proceeds - and usually more like 50% - has to go to charity. In these particular cases, none of the money is being diverted to charities, so in effect they are taking money away from charities."

That's not because they're breaking the law - it's just that this is a grey area. ITV and Quiz TV told us their competitions complied with existing legislation.

In two years from now, a new gambling act will tighten the rules and make sure the quizzes are harder.