The famous imitated line of Michael Caine by Steve Coogan (in The Trip), "She was only sixteen years old!" which Caine never actually said, refers to Petra's character... although she was in her early-twenties playing younger in Get Carter.
Best known for her relatively small but very important role as Michael Caine's niece in the British cult classic Get Carter directed by Mike Hodges.
Daughter of the actor David Markham and the BBC scriptwriter Olive Dehn.