War being generally agreed to be hell, mankind has devised several ways to dekiver it as purgatory if not actual heaven. One of these is humour and, in the contest for the title of Second World War arch-satirist, a strong contender has to be Spike Milligan. The Bristol Old Vic co-production of Adolf Hitler: My Part in His Downfall is based on several of his bitterly comic memoirs.

Tim Carroll's production, for which he and Ben Power wrote the script has a concert party framework. Within this the Battery D soldiers and their officers play jazz (a musical form which elicits the n-word from a disgruntled hearer who prefers something less raucous) on a selection of instruments, sing and generally clown around. There's a certain taste of Oh What a Lovely War and Privates on Parade in the mix.

All the performances are good and the shifts in mood are well managed. Sholto Morgan makes Spike a blend of born anarchist and evolved survivor, winning and losing promotion with the same edgy scepticism. The other players are William Findley as Lt Goldsmith (who is killed in the assault on Tunis], Dominic Gerrard, David Morley Hale and Matthew Devereaux. There's a flexible set by Laura Hopkins which has the right air of improvisation in its arrangements of sandbags, bunk-bed and instruments and the use of microphones is always appropriate.

Many things to admire therefore, and yet the total effect of them isn't as overwhelming as it might have been. The moments of complete seriousness morph into what can sometimes seem too obviously light-hearted – such as when the Last Post is sounded blends into "Anything Goes". Rather than being totally caught up in the lunacy of conflict and the myriad of ways in which those trapped canmake it possible to live with the unspeakable, the show seems to require its audience only to be on the outside, looking in through a blurred viewfinder.