If we were to inform you that Secretary’s central relationship involves a boss who loves to administer rigorous spankings on his desk to an eagerly receptive titular underling, with her knickers round her knees, you might well suppose that Sid James had returned from the grave to star opposite Babs Windsor for one last glorious smut-fest.

A superb idea, undoubtedly, but not of any relevance to Steven Shainberg’s intriguing film. The audacious, if unhinged plot sees downtrodden and self-abusive Lee (played by Maggie ‘sister of Jake’ Gyllenhaal) released from a mental institute back into the arms of her insanely overprotective mother and alcoholic father. She’s in fairly desperate need of some kind of life, which she finds, not through her newfound job as a legal secretary, or her stupendously smitten boyfriend (Davies), but by crawling on her hands and knees through a dumpster for the pleasure of her boss (Spader).

Soon their relationship has blossomed into full scale S & M antics and mind games, and it becomes quite clear that Secretary is a twisted, meditation on the politics of domination and submission.

Basically, think rom-com for sick fucks and you’re there. Although, the movie ultimately covers the same narrative ground as any number of Meg Ryan or Sandra Bullock vehicles – ‘Secretary fucks the boss so she doesn’t have to be the secretary anymore’ – neither Meg nor Sandra have ever pissed themselves on-screen in the name of love.

Fear not, though, for Gyllenhaal manages to convert this act of bladder weakness, and all manner of degrading acts into a stupendous showcase for her acting might. She doesn’t so much vamp it up for the proceedings, as frump it up magnificently, while her opposite number Spader, is on sure ground essaying what feels like the zillionth perv of his career.

An unmissable adult fairytale then, in particular for those who like to get all tucked up with a hot water bottle and a set of electrified nipple clamps at the end of a stressful day.