Media regulator Ofcom wants the Goverment to amend the Communications Act 2003 to tighten the rules covering premium rate phone services.

Ofcom's chief executive officer Ed Richards has written a letter to Culture, Media and Sport Secretary James Purnell in which he said the current regulations were not written to take into account developments in modern broadcasting, such as premium-rate services.

The call comes after a number of high profile phone-in scandals, which Ofcom believes has shaken consumer trust in television.

Last year ITV, Channel 4 and the BBC were involved in scandals over irregularities in television competitions, shows and quizzes. As a result, Ofcom fined Channel 4 £1.5m in December, GMTV £2m and the BBC £50,000.

"Transactional premium rate services (PRS) in participation TV on the scale we have seen in recent years were not envisaged when the Act was drafted," Richards said in the letter.

Although Richards said Ofcom had so far been able use the current Act to regulate all incidents, he warned that as modern technology and broadcasting services grew, the regulator would have insufficient powers to intervene.

"We are concerned that, at some point, technology or service innovation in Participation TV will reach the point where even the most creative interpretation of our editorial regulatory powers could not be brought to bear, " he said.

The Communications Act 2003 currently covers two types of broadcast standards. The first is the regulation of editorial content, which looks at broadcasters’ freedom of expression and how it may effect or offend viewers. It deals with the material that is actually broadcast rather than the processes that brought it to air.

The second type is the regulation of advertising content, which ensures that the content in television adverts is not harmful or offensive.

However, any changes to the Act may not come into effect for some time as, according to Richards, there was a need to wait for "a suitable legislative opportunity".