You Once Said Yes, Roundhouse, London

An evening spent wandering the streets of Camden in north London would not normally warrant a review. But You Once Said Yes, presented by Look Left Look Right as part of LIFT (London International Festival of Theatre), is a meander with a purpose. Audiences assemble at the Roundhouse, are given a cagoule, a backpack and a farewell speech by a travel guide, and then tipped out, one at a time, on to the back streets behind the theatre. From then on you travel alone, your path directed by apparently random encounters with strangers on the street, who engage you in conversation, persuade you to do little tasks for them, and send you further on your way.

It is a little unnerving, to be honest, and to begin with you feel pretty conspicuous and rather ridiculous, with your baggy rainwear and your fluorescent bag. At least two of the people who accost you are so convincingly dramatised that at first you are not sure whether they are actors or real strangers. You have to trust them; you have to say “yes” – even to the point of getting into a car with a strange man. But once you do, and once you let yourself engage with them, the experience becomes a warm and reassuring one.

Unlike You Me Bum Bum Train , a similar interactive experience, you are not expected to perform: rather you need to listen and respond. And gradually you realise that there is a pattern to the journey: that each of the people you meet – people whom you would probably usually ignore or avoid – are down on their luck, struggling with their dreams of making it, desperate in one way or another. Most characters want nothing from you but an ear and a kind word; in return they cannily coax details from you about your own life and aspirations, which they use, delightfully, in the final encounter.

Written by Morgan Lloyd Malcolm and Katie Lyons and directed by Mimi Poskitt, this is one of several interactive shows at this year’s LIFT that focus on the gritty reality for people whose lives have been upended (there’s also 66 Minutes in Damascus, about Syrian detainees, and Unfinished Dream, about refugees, for example). It’s perhaps not for everyone, but this guided tour of the back streets of big city life is, in the end, a rather touching and revealing exercise in empathy.

www.liftfestival.com