S iobhán McSweeney is teaching me her preferred way to enjoy a packet of cheese and onion crisps. She has arranged two matching slabs of Cadbury’s Dairy Milk chocolate, two piles of Tayto crisps and two cans of Guinness on the table in front of us – and is issuing strict instructions. “Don’t swallow!” she booms theatrically, and I freeze, my mouth full of Taytos. The trick, McSweeney explains, is to get the crisps, chocolate and Guinness into your mouth at the same time, and then swill it all around a bit to make a kind of boozy, oniony soup. “See?” McSweeney is watching me carefully to check I am putting all the ingredients into my mouth in the correct order. “It’s delicious! Just delicious!”

McSweeney burst into the public consciousness back in 2018 with Derry Girls , a comedy series about a group of Catholic schoolgirls, set against the background of the Troubles in 1990s Northern Ireland.…