‘I’m less apologetic now’: Kelly Macdonald on her Trainspotting teen highs and hitting her stride in her 40s

She hid in the toilets during the Trainspotting shoot – yet became a screen sensation. As the star plays a police therapist in new Netflix thriller Dept Q, she explains why today’s young female actors leave her in awe

One of the good things about playing a therapist, says Kelly Macdonald with a laugh, is that you get to sit down a lot. There’s a fun scene in the new Netflix thriller Dept Q in which her character, Dr Rachel Irving, weary of her client DCI Carl Morck, plants herself down behind her desk to eat her packed lunch in front of him. Morck may be the kind of troubled detective we’re used to seeing in police dramas, but Irving isn’t a typical therapist. She’s blunt, antagonistic even. It’s a “shitty” job working with police officers, she tells him. Another time she describes him as “doolally”, which in my experience is not something a typical therapist would say; Macdonald, who has had therapy, “but not regularly”, may agree.

In the show – adapted from novels by the Danish author Jussi Adler-Olsen and brought to the screen by Scott Frank, who was also behind the Netflix hit The Queen’s Gambit – Morck is made to see Irving after he survives a shooting. Brilliant but sidelined, Morck is tasked with reviewing cold cases, and moved to a shabby basement office that becomes known as Department Q. The first case for his small crew of misfit detectives is the disappearance of a lawyer four years earlier, who everyone thinks is probably dead. The truth, it soon emerges, is absolutely terrifying.