Frankie Boyle privately admitted that it one of his most controversial jokes should never have aired, the TV executive who signed it off has revealed.

The comedian’s gag about Katie Price’s disabled son Harvey on his Channel 4 show Tramadol Night’s was branded ‘vile’ by the model and earned the broadcaster a slap on the wrist from regulator Ofcom in 2011.

At the time, Channel 4 said it was justified in context, and described as ‘an absurdist satire’ from a comic who treated everyone as fair game, with the broadcaster’s head of comedy Shane Allen saying: ‘We think that it is important that a space on terrestrial TV exists for comedy that takes risks and pushes boundaries’.

However speaking at the BBC Comedy Festival in Belfast last week, Allen revealed that Boyle had, years later, expressed regret that the joke had gone out.

Allen, now chief creative officer at Am I Being Unreasonable? programme-maker Bofollo, said: ‘I signed off that joke, the Katie Price one, and it made the front page.

‘[At the time] I’d said, we should be able to do this, we’re Channel 4, edgy, do it fast, make trouble - all this stuff. Then, years later, Frankie said that it was a mistake, and it slightly fucked [his] career up.’

Ofcom censured Channel 4 for the joke but did not impose a fine or insist on an on-air apology.

Harvey was eight at the time. and Price said: ‘They are saying it is OK to ridicule people - even children - for disability in a way they would not dare over race or sexual orientation. The people who control the channel are endorsing this behaviour and it is disgusting.’

Boyle wasn’t the only comedian to late regret something going out despite clearing broadcasters’ compliance rules, Allen revealed. 

‘I remember McKenzie Crook talking about Detectorists and I asked, "What would you have done differently?" And he said he wouldn't have put such strong language in it, because he's realised that loads of families were watching it, and they loved it, and he thought [the language] was embarrassing.

‘Sometimes [comedians] think it's edgy and cool, and it's not.’

Leanne Buckle, senior editorial complaints adviser at the BBC Trust, added: ‘On Ghosts, one  the comments that came in most often on the audience log was how much they liked it not having strong language in it, and that they were happy to sit down in front of it and just feel relaxed. It isn't a guidelines issue, but the more strong language you include, you are risking driving away your audience.’

She also said bad-language complaints tended to depend on whether viewers liked the person saying it, more than what was said.

‘If they don't like the comedian, they'll complain,’ she explained. ‘Then you can have The Thick Of It, where you just give up on the "fuck" count and receive nothing.

‘It's really difficult to say to comedy writers and performers, but I think it's the one genre where it's absolutely down to quality. If it's great quality, people will go with it. 

‘And the one thing I do think about our audience is they've got a really great bullshit detector. They they can kind of hear if something's gratuitous. 

‘Every word has to really work its passage. So if you are going to use "fuck" a lot, it's got to be [justifiable]. Otherwise it just becomes a bit dull. It becomes like someone saying, "you know", it's really got to work.’

Allen agreed that offence depended on who was delivering the line, saying: ‘ There was a drama, Shetland, I think it was, and people were saying, "We've got lots more fucks" [in the programme]. 

‘So I went through the compliance forms from the previous series, and it was the same [number], but it's just that this series there was a female detective, and people get worked up more about a woman swearing’.’

Asked to name their most ridiculous viewer complaints, Buckle said: We put out Titanic at Christmas an we had a complaint come in from this woman. She said that it started at 8.30pm. She understood that was pre-watershed. She let her daughter stay up to watch it. They had been absolutely gripped by it. She couldn't believe it how upset they were when the boat sank… ‘

Claire Powell, head of compliance at the BBC, said: ‘We get complaints about comedians on streamers and other channels, and we write back and go, "No, it's not on the BBC." 

‘And they come back and go, "no, no, you’ve got to do something about it." What can you do? 

‘Or people complain about a comedian who might be doing some sketches on YouTube, and it's like, "Well, you're the BBC. Deal with it".  Like we've got enough of our own shit to deal with, you know!’