A live instalment of The X Factor has been criticised as ‘unacceptable’ by TV watchdog Ofcom after viewers heard contestant Frankie Cocozza swear on air.

The teenage wannabe, who was later axed from the show because of his behaviour, sparked more than 100 complaints when he embraced his mentor Gary Barlow and said ‘F***ing have it, get in there’ when he was told that he had got through to the next round.

ITV did not apologise for the slip for 44 minutes, and then on a different channel – The Xtra Factor on ITV2 – because no one in the studio or production gallery heard the outburst.

Ofcom said that the word, which was broadcast on the Sunday evening live results show, was ‘clearly audible to viewers who were watching the programme at approximately 20 minutes before the 9pm watershed.

“This was particularly unacceptable in the context of a programme that attracts a substantial family audience,” it said.

Programme-makers admitted that they only became aware of the swearing ‘through monitoring online social media activity’ towards the end of the broadcast.

Channel TV, which compiles the show for ITV, blamed its ‘delayed response’ on the fact that it ‘had to investigate whether or not’ the contestant had sworn and whether the language was broadcast.

It said it had briefed judges, contestants and guests about offensive language and it ‘deeply regretted’ Frankie’s ‘unexpected and unprompted outburst’.

As a result of the error, it now has one member of its team watching the ITV1 feed of the show in a quiet environment.

Ofcom said that the language was ‘unacceptable before the watershed, whatever the audience profile of the channel’. It found the show, which aired in October last year, in breach of the broadcasting code and said that programme-makers did not have good enough systems in place to monitor the live show.