The father of Stuart Lubbock, who was found dead in Michael Barrymore’s pool, has been giving the actor free, if unwanted, publicity by picketing the play in which Barrymore is appearing at the Edinburgh Festival. I make no comment on the rights and wrongs of that case but, ironically enough, Barrymore’s problem in Surviving Spike is that he seems far too respectable for the real-life comedian he’s impersonating. I don’t think I’ve seen such miscasting since Cliff Richard tried to reinvent himself as Heathcliff.

Richard Harris’s play is based on the memoirs of Norma Farnes, who was Spike Milligan’s personal assistant and manager for 36 years, and his subject, like hers, is a man who was frenetic, erratic and, if you want to get clinical about it, pretty bipolar. Subordinate characters make brief, cartoonish appearances: his weary wife, Farnes’s equally fed-up husband, the odd media personage, even a rabbi who objects to Milligan parking his car outside his synagogue. Basically, however, Surviving Spike is about the determination of Jill Halfpenny’s admirable Norma to keep icebergs out of the way of a Titanic that’s already half-holed.

But where’s the mischief, the subversion, the anarchy, the maverick glint in Milligan’s eye? All this is present in Harris’s script, which is often very funny. So a tipsy Spike tells a cop that of course his breathalyser turns green: “I’m Irish.” He advises primary school children to fight for holidays of seven days a week “and if you can’t count, eight”. He signals his recovery from one of his more awful depressions with a jubilant: “Know what I’m going to do? I’m going to rewrite the Bible.”

Harris’s Milligan is a man, at times a megalomaniac, who is predictable only in his unpredictability. He’ll rail at an evil world, then read of a disturbed woman in the paper and buy her a flat. He’ll tell Norma that she must have children, then that children are a curse. He’ll call her in the early hours with the news that, if she were up for auction, he would be the top bidder, then insult her so seriously that she walks out, only to be recalled with a telegram.

Halfpenny gets Norma’s doughty, dogged, unsinkable qualities all right, but Barrymore just can’t do madcap, which means he doesn’t do Milligan. Only at the end, when pathos is required, does he fully succeed. That’s when Spike is terminally ill, mumbling Hail Marys, telling his beads, apologising for his misdeeds. But it’s a long wait until then.

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