Paul Merton: Out of My Head, Richmond Theatre

A leading light in British comedy and one of the most-proven funnymen on the planet, Paul Merton is back with his first UK solo tour since 1999, but Out Of My Head is far from the quality you might expect, being weak virtually from start to finish.

A loosely autobiographical show, it charts the various goings-on in Merton's brain, from childhood into adulthood and early TV success. His struggles with mental health problems are well-known, so he has a more interesting story to tell than most comics - and he at least attempts a refreshing and inventive way of telling it, too. If his intention was to create a slightly trippy take on an old-fashioned variety show, incorporating sketches, stand-up, games, improv and ventriloquism, then he has succeeded.

There's no escaping, though, the flatness of the show tonight. In fact the biggest laugh of the first half is a Max Miller gag that comes when he is talking about his love for music hall. His own storytelling is too often either rambling or lacking in quality gags. For the sketches, a trim-looking Merton is helped out by Lee Simpson, Richard Vranch and Suki Webster – his long-time Comedy Store Players cohorts - but wonky timing and a general looseness make the sketches seem under-rehearsed. Merton does state at the beginning of the show that it has been partially rewritten since he began the tour – a risky move that may pay off later in the run, but doesn't tonight.

Some scenes were just plain awkward, such as the recurring “Little Paul” ventriloquist's dummy, a crowbarred Dragon's Den spoof, and an audio sex tape that is a waste of a good idea. The moments of surrealism – for which Merton is perhaps best known – are hit and miss. I enjoyed the flying bed that he conjures up as a boy, stifled by the strident Sister Glister, and a giant sperm (who wouldn't?), but too often it’s disorientating. It's asking a lot of an audience to suspend its disbelief for some odd asides, then suddenly knuckle down to some candid storytelling about mental health issues.

Despite being light on laughs, the show does zip by. Merton's story is an engaging one told in an ambitious, kaleidoscopic way. Since becoming the star attraction of two British comedy institutions – one of stage (the Comedy Store Players), one of screen (Have I Got News For You) – he's barely had a professional dip, but this is undoubtedly one.