In a disused Royal Mail sorting office in New Oxford Street, there's a welcome return for this inspired and playful promenade event, now boosted by Arts Council funding.
Devised by artists Kate Bond and Morgan Lloyd, it's an immersive experience in which each audience member is the hero (or, in practice, sometimes the villain) of a string of ingeniously realised live scenes.
You're a dentist performing root canal treatment, a cricket umpire mediating in a dispute, a financial adviser explaining your dubious investment tips to an irate client, a gangster in conference with your snooty barrister, a stage manager caught in a blizzard of props, and a window cleaner treated to an unexpected glimpse of a couple making out.
Actually, none of this happens, and participants - critics included - are strictly told not to divulge details of what the show involves. But the flavour of proceedings is very much as I've just suggested. You're obliged to improvise in situations you would never normally encounter.
The ride is exhilarating, strange, a bit messy, and over all too soon. A blend of the surreal and the hyper-real, You Me Bum Bum Train is liberating and unforgettable.
Until December 20, and then from January 5 to January 15 (bumbumtrain.co.uk)
You Me Bum Bum Train
