Diversion

Paul Eddington's Strand spends "Diversion" behaving like a man shedding his own reputation. He takes up with a lady colleague and drinks too much, generally behaving like the department's least reliable senior officer. The episode's whole game is the question it refuses to answer for a long time: has the pressure finally got to him, or is he running a solo operation to flush out a villain? Either way, the department has a problem on its hands, and it is a problem nobody quite knows how to raise with him.

That ambiguity is the engine, and the script is careful not to tip its hand. Strand's scenes can be read twice, once as breakdown and once as performance, and Eddington is good enough to make both readings stick. Years later he would put on the ministerial stripes of Jim Hacker in Yes Minister, but here the polish is off and the character is all loose ends. Craven and Haggerty circle their colleague with the discomfort of men who like him and cannot work out what he is doing. Frederick Jaeger's Commander Fletcher brings the official concern, while Nicolette McKenzie's Beth Summers, John Cairney's Lister, Denis Lill's Tim Summers and a supporting cast of head waiters, police constables and a stripper keep the world around Strand busy.

Peter Hammond wrote it, William Brayne directed. The result is closer to a character study than a chase, and the series is better for stepping out of its usual shape. But watching a reliable man come apart, or appear to, is its own kind of suspense, and the episode trusts the audience to sit with the uncertainty. It is a gamble that pays off, even if it never quite explains itself.

Which reading was true follows you out of the episode. That may be the honest answer to its own question.