Not so long ago if you were a bad boy in one of Her Majesty's Prisons you would be treated with the fine garment. Unlike a conventional straitjacket, a British prison jacket has no sleeves. Instead it has a pair of inside pockets for the arms. The jacket does not look very secure and that is the problem. In order to make it secure, your host would choose a jacket a size too small and then buckle the back and double crotch straps very tightly. Escape was no longer your concern, breathing was your concern.