Radio, film, and television actor Ron Donachie has an extensive career spanning 40 years, most recently known to fans for his appearance in Waterloo Road and playing the role of Ser Rodrik Cassel in Game of Thrones. Don's character in Screws is said to be "lazy and miserable" and the idea of a stereotypical prison officer that the public will have an image of. A bit of a drifter, he spent some unsuccessful time in the forces, leaving to become a security guard, before falling into prison work. Unintentionally funny and constantly avoiding any physical work, Don is on a count down to his retirement, offering a stream of excuses for not showing up when anything kicks off in the prison.