Not to Be Trusted

Dr Clifford is an eminent scientist on loan to a top-secret research establishment, and somebody wants to know if he is a security risk. The question lands on Inman's desk, and it is the kind of question with no comfortable answer, because the establishment has suddenly started leaking. The suspicion is that the man has been got at. The alternative, which nobody wants to say out loud, is that the leak is someone else's work and Clifford is the patsy. Either way, somebody inside the establishment is talking, and the establishment cannot live with that.

George Markstein and Martin Worth wrote it, Guy Verney directed, and the episode does its best work in the space between those two possibilities. The team turns over everyone Dr Clifford touches: his wife Brenda, colleagues named Falcon, Karin and Gillian Heyman, the ministry figure of Sir Hugh Lodge, and Schaeffer, who might be the voice of reason or the voice of trouble.

And the show refuses the easy version of the story. Suspicion is the currency of this world, and the episode keeps asking how you protect secrets without wrecking the people who keep them. It is a quiet hour, mostly rooms and files and careful questions, and there is no shootout and no chase; the danger is all in the looking. The sympathies sit with the man under suspicion, which is a choice worth noticing.

Derren Nesbitt's Jordan and Fulton Mackay's Inman anchor it, with Morris Perry as Moxon, William Lucas as Dr Clifford, Alethea Charlton as Brenda Clifford, Emrys Jones as Falcon, Ania Marson as Karin, Maureen Davis as Gillian Heyman, Ronald Russell as Sir Hugh Lodge and Denis Goacher as Schaeffer.

In a building full of classified papers, trust is a luxury nobody can afford. The episode lets the question sit there. And whatever the truth of it, the damage is already done: the trust is gone.