Set in a dank London when people smoked on the tube and everywhere else, Misbehaviour views the past not through rose-tinted spectacles but through the lens of feminist outrage.

The film might look like a perky British period comedy but it’s far more serious than that, despite a based-on-truth storyline involving Womens’ Lib, Miss World, Rhys Ifans in a gold cloak and, your host, American comedy legend Bob Hope (Greg Kinnear doing a fine physical impression).

It tells of a crucial pop-cultural moment when the nascent Womens’ Lib movement interrupted the 1970 Miss World finals before a live global TV audience of 100 million just as the pageant itself was about to announce its first ever black winner, Miss Grenada.

Among an impressive and likeable cast, lovely performances by Keira Knightley and Gugu Mbatha-Raw give the film its spark and heart. Keira is Sally Alexander, the “mature, mature student” cajoled (by Jessie Buckley in dungarees) into activism; Gugu is Grenadian Jennifer Hosten, the beauty contestant determined to show her intelligence and grace under pressure. There’s a great scene between the two of them, two worlds coming together yet colliding.

Misbehaviour beautifully captures the mood (and decor) of a changing era with all its brown crockery, macrame and spider plants, and all of its institutional sexism, where the Miss World girls in their swimsuits don’t look sexy but freezing cold, and where Kinnear’s Bob Hope can offer a pretty new assistant a drink: “Will it be Scotch and Sofa or Gin and Platonic?” Leslie Manville’s Dolores Hope rolls her eyes witheringly in the background.

The film won’t stand for this sexist stuff quite so patiently. “We are angry” reads a placard, and that certainly comes through the fug of smoke, perhaps to the detriment of the overall movie, which never quite allows itself to be entertaining, such is the outrage that society used to get away with this sort of thing.

Director Philippa Lowthorpe balances many story lines and brings them together with impressive control, even if I wished she’d occasionally have a bit more of a laugh with it, or at it. But you can’t fault the film’s passion in recognising a crowning moment in British social history and telling it from a fresh and unforgiving female perspective.