The British equivalent of polish jokes, playing on the sterotypic ilogicity of Irishmen. They often start: An Englishman a Scotsman and an Irishman were..
Examples include:
An Englishman a Scotsman and an Irishman were discussing what the most important invention was. The Englishman said, "I think the heart transplant was the greatest invention ever, because I had a dodgy heart, and it'd be curtains for me if it wasn't for a heart transplants." The Scotsman said, "I think liver transplants are the best, as I'm partial to a bit of whiskey, and it'd be curtains for me if I hadn't replaced my liver." The Irishman then said, "I think blinds were the greatest invention ever, otherwise it'd be curtains for all of us."