For a comedian as unapologetically offensive as Frankie Boyle upsetting the audience is an occupational hazard. Nonetheless this was, as he is said to have described it, "the most excruciating moment of my career".
Boyle, who became famous with his furious, scathing humour on BBC2's Mock the Week, has seemingly met his match in the form of a Hampshire mother who, attending last night's opening date of the Scottish comic's national tour, objected to a routine in which he mocked people with Down's syndrome for, among other things, their haircuts, clothes and voices.
Sharon Smith – a fan of his comedy – was sitting in the front row of Reading's Hexagon theatre and Boyle spotted her discomfort. Seeking to further the running joke, he challenged her. The response came: Smith's five-year-old daughter, Tanzie, has Down's syndrome, and she found his jokes very upsetting. Cue a deeply uncomfortable moment, even for the famously unrepentant Boyle.
A blog account of events by Smith, 37, from Hook, near Basingstoke, has since become a Twitter sensation. Among those sending tweets of support today was the Gavin and Stacey actor Mathew Horne, who described Boyle's targeting of Down's syndrome as "rubbish".
Smith said she was aware of Boyle's style – the BBC Trust last year condemned a Mock the Week episode in which he described the Olympic swimmer Rebecca Adlington as "someone who's looking at themselves in the back of a spoon".
She told the Guardian: "I knew what to expect. I put myself in the situation. I'm a comedy fan, so is my husband, we see a lot of stand-up. I was even ready for some jokes about disability, and decided I'd try to ignore them."
But as Boyle launched into a long, seemingly semi-improvised skit about people with Down's, including exaggerated mimicry of their voices, Smith said she became upset. Her husband asked if she wanted to stay, and Boyle asked the couple why they were talking.
After trying, unsuccessfully, to wave him away, Smith responded. "I said I was the mother of a child with Down's and I found what he was saying a bit upsetting. He said, 'Oh, but it's true, isn't it?' I said it wasn't true."
While much of the audience laughed, Boyle looked unsettled, Smith said, and launched into a long explanation of why his humour tended to be so vicious. She added: "He said it was 'the most excruciating moment of my career'."
Boyle's caustic humour has done little to mar his popularity, with his memoir, My Shit Life So Far, proving a surprise Christmas bestseller. No longer appearing on Mock the Week, he has begun a 113-date tour, titled I Would Happily Punch Every One of You in the Face, which is almost sold out.
Smith said: "What bothered me most was that it was very childish, playground stuff, really. I'd have had more respect for him if he'd come up with something new or funny. But it was so ignorant. Tanzie is beautiful and intelligent. She goes to the local primary school and most of the time you forget she's got Down's."
Her blog post was, she added, just a way of recounting the experience to friends, and she never expected it to attract attention. "More than anything, I hope this makes him rethink his views on Down's. He's totally wrong."
Boyle's agent said he had no comment.