Torchwood (Seasons 1–4)

Torchwood (2006–2011) is the adult Doctor Who spin-off you can watch online on iFILM. Beneath a Cardiff waterfront sits a secret institute that catches whatever falls to Earth through a rift in time and space.

Running the team is Captain Jack Harkness (John Barrowman), an immortal con man with a long, murky past. Around him: ex-cop Gwen Cooper (Eve Myles), soft-spoken archivist Ianto Jones, prickly medic Owen and tech whiz Toshiko. They recover alien tech, hunt down whatever slipped through, and clean up the cases the government would rather bury. The longer it runs, the less it's about gadgets and the more it's about the cost of every call they make.

Across four series the tone shifts hard, peaking with Children of Earth, a five-night event that's about as bleak as British TV got that decade. Creator Russell T Davies wrote it for grown-ups, free of the family-hour rules. It's for viewers who want sci-fi where the alien threat is really an excuse to dig into people. Stream every season of Torchwood online on iFILM.