Rob Brydon, Hexagon, Reading

When Rob Brydon's support act, Hal Cruttenden, announces himself, there's the customary puzzlement from the section of the audience that didn't realise there was a warm-up. When Brydon announces himself, after the interval, there seemed to be a smaller group that hadn't realised that this was the Welshman unmasked, and not appearing as Keith Barret from Marion and Geoff, nor even doing more than a brief refrain of Uncle Bryn from Gavin and Stacey. No, this was Rob Brydon of hit and hope. Anyone disappointed by this realisation would have it reinforced by the end of the show and join me in my personal disappointment at what was a rather hotchpotch effort from a comic of great poise and skill.

Brydon launches straight into the first third of the show, an apocryphal account of the birth of his fourth child. Tom's origins are depicted using a Strictly Ballroom-style critique of Brydon's love-making technique that allows Brydon to show his skill for impressions by mimicking each of the judging panel, a skill that never quite escapes a "gratuitous" context.

With this enjoyable set piece over, proceedings fragment. Brydon portrays his fellow countrymen as insipid, not raising them much above the "safe" punch bag they became on the post-PC comedy circuit.

As with his previous tour as Keith Barret, audience interaction has a significant part to play in Brydon's show. However, Brydon's efforts are unfocused and undermined by the audience's unwillingness to play along, or, at least, by his constant referral to their antagonism. Not that morsels of comedy gold aren't unearthed – such as the 16-year-old girl called Devon – but Brydon's momentum at this point won't allow him to mine this much further.

The interaction portion of the evening is ultimately overplayed, while the final section of the show relies on Brydon taking requests for musical numbers. I am tempted to suggest: "Do you know the one called 'Why have you written half a show?'" Of course, this would be churlish – more so, perhaps, than the extent Brydon's persona is deficient in charm compared with his Barret character. But such is my disappointment that Brydon has hit the comedy "off switch" by unplugging his character act.

Touring to 23 May ( www.robbrydon.com)