Alien

The deal on paper is simple. Gunter Hellman, a student revolutionary, is let into Britain with his wife Gisela so he can finish his studies, on the strict condition that he stays out of politics. "Alien" is about what happens when Special Branch suspects he has broken the deal. Craven and Haggerty pay him a call, and the visit turns into a slow squeeze. The drama is quieter than that: a man being watched, and the couple feeling the weight of it.

The episode is a study in institutional patience. Nothing dramatic happens in a hurry; the pressure comes from interviews and surveillance, plus the quiet weight of the permit itself. Damien Thomas plays Gunter with an unsettling stillness, and Ann Firbank's Gisela watches her husband's careful performance with something close to dread. Paul Eddington's Strand looks on, Frederick Jaeger's Commander Fletcher keeps the official line, and the academic world gets its turn through Susan Tebbs's Dr. Barbara Latimer, Keith Buckley's Martin Kingswood and Gareth Thomas's Steve Ryman. The academics around Hellman are a reminder that in 1974 student radicalism was not a museum piece; it was a live worry for the people who stamped the permits.

Ray Jenkins wrote it, Douglas Camfield directed. Camfield had a long history with Doctor Who, and Patrick Troughton, a few years out of the TARDIS, turns up as Professor Frederick Denny, which makes the episode a small reunion of Who alumni for anyone paying attention. The casting gives the whole thing a comfortable, familiar texture.

The point lands quietly: a country can grant refuge and still treat the refugee as a problem. Hellman is suspected of exactly what he promised not to do. But the episode never lets you forget the terms of the bargain, and it keeps you wondering whether he kept his side of them.