Many Americans aren't familiar with Boyle, but across the Atlantic the comic is notorious for his disregard for boundaries. It reads like a laundry list of dumb shit, or the lunch-room banter of middle school boys: He’s poked fun at disabled athletes participating in the Paralympics; he’s said made offensive remarks about the Queen; and he’s performed routines about those suffering from Down syndrome. It goes without saying that his routines frequently involve potentially racist and sexist material.
Because of these things, he's faced the BBC numerous times over allegations that his jokes are too offensive to be broadcast. Thing is, it doesn't appear to have hurt his career.