The Mint is one of ITV Play's biggest hits

The Commission believes networks are charging callers up to 60p a minute for entry to competitions which require no skill or knowledge.

This is potentially against the 1976 Lotteries and Amusements Act, it adds.

A lottery requires a licence, which channels like ITV Play do not have, and 20% of the revenues to go to charity.

"Many of the commercial schemes which currently operate as competitions are, in the commission's view, [complex lotteries]," said a spokesman.

"Good examples are the TV quiz shows on dedicated channels which have sprung up in the last two or three years.

"All such channels will either have to stop operating altogether or operate under the provisions relating to lotteries or ensure that they operate such that they fall within the provisions relating to either prize competitions or free draws."

Profits

Broadcasters - not only ITV Play, but also Big Game TV and Avago - have been using a legal grey area to classify their games as "prize competitions" by allowing free entry via their websites.

ITV Play has made more than �9m in profits for the network since its launch in April.

The channel allows viewers at home to take part in question-and-answer cash prize competitions by using their phones to call a premium rate line. The top prizes are up to �100,000.

"ITV is a responsible broadcaster and we take this position very seriously," said a spokesman for ITV Play.

"Our programmes exceed all current regulatory guidelines for prize competitions, with routes of entry via phone, text and for free via the web.

"All of these entry methods are clearly displayed on screen and regularly referred to by the presenters. We have created over 10,000 winners and given away over �6m in prizes since end of March."