"Live and edgy broadcasting carries risks but Radio 1's Controller, Andy Parfitt, has made it clear to both staff and presenters that inappropriate language is unacceptable," it said in a statement.

If the rules are breached twice within 12 months, the presenter will suffer a financial penalty.

Radio 1 said these new procedures were already in place, but Moyles would not be fined on this occasion.

However, the station told Ofcom that Mr Parfitt had raised the issue of foul language with the DJ "who had given an assurance that his use of language would be more carefully managed".

Clearly unsuitable

A prank phone-call on Scott Mills' afternoon show, which contained bleeped-out swear words, was found to be "overtly aggressive" and "clearly unsuitable for broadcast".

Moyles' breakfast show was found to be in breach of broadcasting guidelines for a third time when it allowed a guest to swear during an interview.

In the latter case, Ofcom said it was satisfied that the presenter had asked the guest not to swear.

It also welcomed the fact that Radio 1 had reminded production teams how to deal with language from contributors in light of the breach.

However, the watchdog said it had serious concerns about "the number and, in some cases, the seriousness of compliance issues that have arisen" at the station.

"We recognise that Radio 1 aims to produce imaginative and innovative programming but the station also attracts a wide-ranging audience, including large numbers of children," it said.

"Any future similarly serious compliance issues may result in the consideration of further regulatory action."

BBC NEWS.