Kirsty Young's castaway is Jed Mercurio. Creator of Line of Duty, and an award-winning TV writer, producer, director and novelist, he is one of the few British script-writers to work as an American-style show-runner. A former hospital doctor and RAF officer, he has been ranked among UK television's leading writers by TV industry magazine Broadcast.

His Italian parents moved to the UK after the Second World War and he was brought up in Cannock in the Midlands. Keen on science as a child, with dreams of becoming an astronaut, he studied medicine at Birmingham University. While there, he applied for the RAF medical doctor programme and learned to fly.

While he was working as a hospital doctor, he answered an advertisement in the British Medical Journal seeking advisors for a medical TV drama. Despite negligible writing experience, he went on to script the BBC medical drama Cardiac Arrest. Its continuing success led him to leave medicine and embark on a successful career as a scriptwriter. His chief works for TV are the series Line of Duty, Bodies, The Grimleys and Cardiac Arrest. He's also written books: Bodies; Ascent; American Adulterer, and for children, The Penguin Expedition.

Producer: Cathy Drysdale.