In the nicest possible way, Eva Green can suggest demonic possession with the merest arch of an eyebrow, or a wolfish flash of teeth. She is such a dark heart that when she turns up in this film playing a children’s fashion designer, I half expected her to gobble up one of the little darlings whole. But no, she is not the angel of death in this politically engaged London-set horror. Not to begin with at least; that role belongs to a Filipina housekeeper called Diana (Chai Fonacier).

Nocebo opens with Green’s designer Christine putting on a fashion show. As the kids bounce up the runway, she takes a phone call. Her face slackens as she repeats the horror of what she’s hearing (“… pulling out bodies?”). Eight months later, jittery and on edge, Christine seems to be recovering from a breakdown. But, on the bright side, she’s got a commission from a kidswear company that plasters its cheap prices across adverts: “T-shirt £3”.

Then comes a knock at the front of door of her extremely large, expensively decorated house. This is Diana, a young woman from the Philippines who tells Christine that she hired her as a housekeeper and nanny to her young daughter. Now, Christine has been suffering from memory loss, so she lets Diana in. You’ll have to swallow the sheer implausibility of this. (What, no discussion of wages or police checks?) Pretty soon Diana seems to have her boss under control: Christine even believes that Diana’s folk remedies are helping with her anxiety. Her husband, Felix (Mark Strong), is sceptical.

Director Lorcan Finnegan, working with a script by Garret Shanley, creates some unsettling moments and there are sharp prickles of commentary about our attitude to fast fashion and the workers who make our clothes. But it’s a film that runs out of steam in the second half, partly because of a plot revelation that is visible, if not from space, but from about 10 minutes into the film.

• Nocebo is released on 9 December in cinemas.