Lawson's Last Stand

A lieutenant-colonel walks out of an army psychiatric hospital and vanishes. That alone would be enough to worry the people who run things. But Peter Lawson isn't just any patient. He's carrying NATO secrets about the world's most toxic gas, and the question of the hour is simple: has he been lifted by foreign agents, or is he off on a deranged campaign of his own to put the Britishness back into Britain? Either way, the man is walking around with the recipe for a very bad day in his head, and CI5's clock is not a patient one.

Bodie and Doyle get the manhunt. The trail takes them into the fringes of an old soldier's world, and the episode keeps both possibilities in the air for most of its running time. Every lead that looks like an abduction could just as easily be a private crusade. The answer, when it comes, is explosive in the literal sense. Before that, though, there's a proper chase on, with the army and CI5 tripping over each other and the missing colonel always one step ahead.

Brian Clemens and Ranald Graham wrote it, Ian Sharp directed. Michael Culver makes Lawson a genuinely unsettling presence, a man whose madness and his loyalty to his country have become the same thing; Star Wars fans know him better as the Imperial officer whose apology to Darth Vader is not accepted. John Hallam's Tug Willis, Michael Angelis's Len Clarke, Stephen Greif's Dr. Lowe, Eve Bland's Doreen, Donald Pickering's Brigadier Tennant and Helen Cherry's Lavinia Lawson fill out the hunt.

It's the kind of story the show does well: a state secret in the hands of a man pushed past his limits, and the machinery sent to bring him home before he can hurt anyone or be hurt. The gas never quite becomes the point. The point is the man holding it, and what the years of holding it have done to him.