Months before Primetime , Lance Oppenheim’s grimy and propulsive film about the NBC paedophile-hunter series To Catch a Predator , arrived in cinemas, the internet had already stripped its trailers for parts. Robert Pattinson’s multifariously uncanny impression of TV host Chris Hansen had been plucked and reconfigured into a raft of frivolous memes. “You see how this looks, right,” he coos, smug and sinister, to a prospective child sex offender, in a clip that, if you’re anything like me, you’ll have encountered dozens of times before seeing it in context.

Overcoming this sort of memeification is no small feat, but Primetime , to its credit, leaves scant time to be glib. The story begins in the thick of things, with To Catch a Predator already a well-oiled – if flagrantly unethical – machine.…