Frankie Boyle reprises his ugly attack on swimmer Rebecca Adlington

If at first they don't succeed, most Olympians will aim to try again four years later. The same goes for Frankie Boyle, who last night returned to the subject of swimmer Rebecca Adlington's appearance, despite facing strong criticisms for similar jokes during the last Olympics.

Last week, the provocative Scottish comedian tweeted to his 800,000 followers: "I worry that Rebecca Adlington will have an unfair advantage in the swimming by possessing a dolphin's face."

The joke, which has been retweeted almost 3,000 times since Thursday, directly echoes those that Boyle made on Mock the Week in 2008, which caused Adlington to complain that the BBC had let the comedian off lightly after the BBC Trust judged his comments unjustifiable.

After the British swimmer's double gold medal-winning stint at the Beijing Olympics, Boyle joked: "The thing that nobody really said about Rebecca Adlington is that she looks pretty weird. She looks like someone who's looking at themselves in the back of a spoon."

He caused further offence by returning to the subject in the same show, saying: "When she arrived back on the flight she met her boyfriend. Did you see her boyfriend? He was really attractive. He was like a male model. So from that I have deduced that Rebecca Adlington is very dirty."

The BBC received an initial 75 complaints, but took no action despite the BBC Trust deeming the jokes "humiliating" and "offensive." Despite the trust's ruling that the joke should never have been broadcast, Boyle refused to apologise. He has subsequently left the panel show, but denied allegations that he had been fired.

Comedian David Walliams waded into the fray on Twitter, saying: "I have met and spoken on the phone to double Olympic gold medal swimmer Rebecca Adlington … And she is a beautiful woman, inside and out it. Is disappointing that anyone would want to be mean about her appearance."

Adlington, at least, seems not to have been fazed by the comedian's heckling. She won bronze in the 400m freestyle, recording a faster time than her gold-medal winning performance in Beijing.