Ninety Per Cent Proof

The third series opens with Brian Clemens — the creator of The Avengers and The New Avengers, one of the defining names of British television crime — writing an episode that puts Bergerac's own credibility on trial. "Ninety Per Cent Proof" begins in court, where Bergerac's case against an arsonist, Jerry Le Favre, collapses: the magistrate orders a jury trial after the defence implies Bergerac was operating outside the Bureau's remit. The petrol canisters that would have proved arson are the same ones the fire destroyed. Humiliated, Bergerac goes for a drink. What happens next is the episode's central problem: Bergerac claims he was forced to drink, that a red-haired Irishwoman, Suzy Walsh, asked his help against her violent husband, and that he witnessed her murder before being knocked unconscious. He is found drunk, rambling, and nobody believes a word of it.

It is a superb premise, and Clemens — a master of the twist — works it for everything it is worth. Norma West and Niall Padden play the Walsh couple at the centre of the allegation, and the episode keeps the audience uncertain how much of Bergerac's account is alcohol and how much is the truth that alcohol has been used to bury. Robert Young directs with a balance of dark comedy and genuine strain: the sight of the Bureau's best detective staggering through the Royal Yacht bar, too drunk to be believed, is played for real discomfort.

The investigation, once Bergerac has sobered enough to be heard, is a reconstruction of a night he barely remembers — and the arson case he lost is waiting at the other end of it. Clemens ties the two threads together with the neatness of a man who built a career on doing exactly that, and the resolution turns on the same principle as the opener: ninety per cent proof, and the last ten per cent being the difference between a burned reputation and a closed case.

As a season opener it is unusual and confident. It puts the lead at the centre of his own disaster, tests whether the audience will trust him, and rewards the trust. Nettles plays the hungover, humiliated Bergerac with a raggedness the series had not asked of him before, and the hour lands because the character's shame is real. A strong, character-driven start to the third year.