Leo the Last is a 1970 British drama film co-written and directed by John Boorman, based on the play The Prince by George Tabori, starring Marcello Mastroianni and Billie Whitelaw.

The ennui-afflicted heir to a deposed European throne returns to his father's house in West London to find that the neighbourhood has become a slum.

Gradually he is stirred from his emotional detachment to try to assist her, a development that confuses, alarms, and angers his parasitic entourage: Margaret, his social climber fiancée; Max, the shady family lawyer (who for reasons never directly explained is desperate for Leo to marry Margaret); David, his quack doctor; and Laszlo, the household manager, and apparent leader of a secret society aiming to restore the dynasty.

A pacifist and liberal idealist with no interest in reigning, Leo is relieved when Laszlo confesses that the society is a fraud, but furious when he discovers that he himself is the owner of the slum and his life of wealth and privilege has been paid for from its rents.

Leo becomes the unlikeliest of revolutionaries, rallying the denizens of the slum with the aid of Salambo and her charismatic working-class hero boyfriend Roscoe.

The intellectual and professional class (in the person of the socialite, the doctor, and the lawyer) is quickly overcome, but the capitalists and petite bourgeoisie (pimp, rent collector, shopkeeper, and real estate shareholders) prove tougher, fortifying themselves in Leo's mansion.

United Artists executive David Picker later said: The film was worth making, but not at the price it cost ... no one had any money to lavish on creating an audience for a picture if there was the slightest doubt that it would find one lining up to see it.

The commissioned author, unlikely as a tie-in novelist, but no doubt chosen for the assignment based on his counter-culture profile, was Beat writer and gay activist Leo Skir.