He was a maverick, a one-off, a free-associating comedy anarchist. So what’s the point in paying tribute to Spike Milligan with a bio-play that is safe, conventional and cosy? The tone of Surviving Spike by Richard Harris has far more in common with the mainstream appeal of star Michael Barrymore than anything the eccentric Milligan produced. The former Goon is being sanitised for the nostalgia market.

Not that Barrymore is to blame. It’s hard to say whether the Strike it Lucky star makes a convincing impression of Milligan because so little of the script requires him to do so. Charting the three-decade relationship between Milligan and his secretary-turned-manager Norma Farnes (Jill Halfpenny), the play indulges the memory of the comedian without showing any feel for his comedic genius.

What Barrymore is able to bring, however, is a feel for the swings of manic depression that plagued the comedian and, surprisingly, for the frustrating infirmities of his final years. The play is a very ordinary trot through the events related in Farnes’ Spike: An Intimate Memoir, but it does capture something of the volatile relationship between the two. This is enough to make it pleasantly watchable, but neither of those words should be associated with Milligan.

Assembly Rooms, 623 3030, until 25 Aug (not 11), 4.15pm, £17.50–£20 (£15–£18).