Official Secrets (2019) BBC2, 10pm

An impressive cast retells the true story of Katharine Gun, the whistleblowing linguist who, while working at GCHQ in 2003, was accused of breaching the Official Secrets Act by leaking a memo in the lead-up to the Iraq war. Keira Knightley (above) plays her, while Matt Smith co-stars as the journalist who broke the story. ★★★★