Everyone wants to be liked; it’s a natural human instinct. Some of us worry about it more than others, true, but we all want to belong somewhere – and if we’re really honest, we’ve probably all told a little white lie or exaggerated a bit at some point to impress someone we admire. But what happens when that need for other people’s approval gets out of hand, and how far can you bend the truth before it snaps completely?

Sam. The Good Person is set at a support group meeting, where regular attendee Sam has finally been persuaded to open up about his big problem: he’s so obsessed with what other people think of him that he’ll say and do literally anything, however detached from reality, to fit in. At first it’s funny, but a few panicked fibs in the heat of the moment soon begin to turn into active manipulation, and we’re ultimately left looking back and wondering if we too have fallen victim to his lies.

Writer and performer Declan Perring is a master storyteller with excellent comic timing. He switches moods, accents and characters in the blink of an eye, and engages very comfortably with the members of his support group, who are “played” by members of the audience seated in a circle around him. His story might sound extreme – is it really possible to have a five-year relationship based entirely on a fiction? – and yet the fact is despite Sam’s early and frank admission that he’s a compulsive liar, we nonetheless do immediately like and trust him. He’s funny, and endearingly self-conscious, and he seems to genuinely worry – albeit to an unhealthy degree – about how his actions affect other people, even if it’s something as innocuous as waiting for a kettle to boil in a quiet room. At first, he seems like someone we can all relate to.

Even later (once we’ve established he definitely isn’t someone we relate to) when we hear about – and see with devastating clarity, despite there being nothing to look at; a testament to the power of Perring’s physical performance – the horrific event that’s ultimately brought him to this group, we can’t help but feel bad for him and everything he’s gone through. And that only makes the play’s final twist all the more unsettling.

Ironically in light of the subject matter, Stephanie Withers’ production has a feeling of great authenticity throughout, enhanced by the seating of members of the audience on stage. Though none of them is called on to say a word, their presence means that we don’t go in feeling that we’re watching an actor give a performance – a point that becomes increasingly key as the play goes on. There’s stellar work too from lighting and sound designers Will Alder and Nick Clinch, who perfectly keep pace with Sam’s mood in all its ups and downs. Just like his story, their work often makes for a deeply uncomfortable audience experience, which is reflected too in Perring’s spellbinding performance.

What’s most striking about Sam. The Good Person is the way it takes a perfectly normal, even admirable, sentiment – the desire to be a good person, someone others admire and want to be around – and twists it into something genuinely disturbing. Because we recognise ourselves in Sam early on, the play suddenly makes you feel you’re only one step away from following him down that dark path… This is a cleverly written, darkly humorous and exquisitely performed piece of theatre that will make you question everything you thought you knew about yourself and the people you love. It’s also a lot more fun than I just made it sound, so let’s hope this short run – which ends on Saturday – isn’t the last we’ve seen of Sam.

Can’t see the map on iPhone? Try turning your phone to landscape and that should sort it. I don’t know why but I’m working on it…