Mark Thomas, BAC review - impassioned polemic about the NHS

Mark Thomas issues a health warning for Check-Up: Our NHS at 70  at Battersea Arts Centre  – “This show contains swearing, a video of an operation on a stomach and a description of being in A&E when a patient dies.” Indeed it does, but it also contains a heartfelt love letter to the health service Thomas was born in and, as a lifelong socialist, hopes to die in.

The show, a highly entertaining 75 minutes, is based on a series of interviews that Thomas conducted with leading experts in the NHS and a month-long residency shadowing doctors and nurses in a hospital group in London. He covers a brief history of the NHS, making the story personal with his own family's memories of pre-NHS illness and accidents, and the transformative nature of Aneurin Bevan's brainchild, which came into being on 5 July 1948. In the first two years alone, Thomas says, 17 million pairs of free NHS glasses were prescribed – meaning many of those people could see and read properly for the first time.

But while Thomas – rightly, in my view – describes the NHS as a wonderful thing, he puts it firmly in context. It isn't the best health service in the world (anybody claiming so is British exceptionalism at work again, he notes in a Brexit sidenote), as UK cancer outcomes attest, or several other statistics that could be used as a fair metric. But, properly managed and funded, it could and should be the best, and that is his message in this impassioned polemic.

This doesn't sound much like a comedy show, and in truth I suppose it isn't. But it is very funny in parts because Thomas, now a master of this type of entertainment – a witty lecture that combines stand-up comedy, theatre and storytelling – invests it with some zinging one-liners. As directed by Nicolas Kent, it bounces along and Thomas, talking a mile a minute to get all the facts across, assumes the accents and mannerisms of those he interviewed as he relays what they told him about their work.

Among several anecdotes from the front line, Thomas tells of the day he shadowed a bariatric surgeon who was stapling a 28-stone man's stomach (the procedure we are warned about and see a snippet of on the large onstage screen). As jazz plays, Thomas intones in the surgeon's voice “staple, cut, staple”, as if to the beat of the music, in an affectionate caricature of him. Another senior doctor tells him to eat a banana before shadowing his long A&E shift because if Thomas faints he'll be annoyed, as he will become another patient to care for.

As a first-person report yes, it's biased, but an underfunded, overworked and undervalued NHS needs all the supporters it can get – and Thomas warns that it is being privatised under our very noses. Despite the comedy, this is a deadly serious and important show.

• Mark Thomas is at Battersea Arts Centre until 4 May
• Read more comedy on theartsdesk