One Way Pendulum, described on the title page as "A Farce in a New Dimension", is a play by N. F. Simpson. It was first performed at the Royal Court Theatre, London on 22 December 1959, transferred to the Criterion Theatre and ran until 11 June 1960. The play was later adapted for the cinema.
N. F. Simpson had come late to writing plays. In 1957, when in his late thirties, his play A Resounding Tinkle had won third prize in a playwriting competition organised by Kenneth Tynan of The Observer. One Way Pendulum was Simpson's second full length play.
The play, in the absurdist genre, contains numerous diversions and non-sequiturs, such as people riding to hounds on camels, and a game of three-handed whist played by two participants, without cards, in the dark, but the core consists of the efforts of the son of the house, Kirby, to teach a collection of talking weight machines, which he has stolen, to sing the Hallelujah chorus from Messiah, and his father's decision to build a replica of the Old Bailey in the sitting room. Elsewhere in the household Mrs Groomkirby is so obsessed with cooking that she employs a neighbour to come in twice a week to help eat the food, and the daughter, Sylvia is dissatisfied with the length of her arms. In Mr Groomkirby's home-made Old Bailey a judge and counsel appear; Kirby is put on trial for mass murder (he kills people so as to indulge his passion for wearing black mourning).
The Times found the tone of the play too relentlessly illogical to be consistently funny. Tynan took a contrasting view: "On the strength of his new play, One Way Pendulum, I suspect Mr Simpson to be the possessor of the subtlest mind ever devoted by an Englishman to the writing of farce".Later critical opinion has been that the play is probably Simpson's finest. The critic Michael Coveney commented in 2011 that the author "mixed a comic brew that derived more recognisably from the worlds of Lewis Carroll, W. S. Gilbert and the Goons."