S04 E03 - Traitor

Series 4 aired on BBC1, Mondays, mostly 7:15 p.m., 28 September to 21 December 1981. Producer: Vere Lorrimer. It averaged 8.49 million viewers on original airing in the UK, with an average chart position of 74, a drop of about a million viewers on that of Series 3, and a chart position on par with that of Series 2. All 13 episodes were repeated on BBC1, Saturdays, mostly 5:25 p.m., 4 June to 27 August 1983.

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