Over the three days in question, in May 1940, with the war underway but not going well, Winston Churchill wrestles with his cabinet over whether to sue for peace with Hitler, as Italy enters the affray, or stand firm as France and Belgium subside into neutrality.

It’s a sort of cliff-hanger – “the tightest corner for Great Britain since 1066,” remarks the lizard-like Lord Halifax — in Ben Brown’s efficiently written waistcoat and watch-chain drama; but with only one possible outcome, which we already know.

And the significance of what doesn’t happen is awkwardly underlined by the narrator/commentator, the young secretary Jock Colville (James Alper) who introduces Churchill and his chums kneeling at prayer in front of the cabinet table and a large map of Europe.

On the one hand there is Jeremy Clyde’s silky Lord Halifax (who really only did have one hand) and Robert Demeger’s blank and desiccated Neville Chamberlain, appeasers both.

On the other, Michael Sheldon’s mole-like, moustachioed Clement Attlee – “a modest little man with plenty to be modest about” said Churchill — and Dicken Ashworth’s “man of the people” Arthur Greenwood, Clem’s deputy, who reports an appetite for war in the industrial heartlands.

In the middle, the glowering, sweating, ferocious bulldog figure of Warren Clarke’s Churchill chairs the debate with surprising patience, dealing in the second, slightly incomprehensible scene, with the cowardly French prime minister in a green suit (Timothy Kightly), backing out of every door that opens in front of him.

Alan Strachan’s careful production gives full value to the slightest nuance in argument, the pained submissions of Halifax, the cooperative decency of Attlee, the hollow-eyed reminiscences of Chamberlain, and the latter’s gradual shift away from shiftiness; but there’s something incurably inert about the piece until we hear what we’ve come for: Churchill, on his feet, addressing the House.

At last, the rhetoric kicks in, and the phrases roll out: it is better to fight on and perish than to lose as slaves, a rallying call that complements his cabinet threat to arm women and children with knives and to fire his last bullets at any invading enemy from inside a pillar box.

The play is far less compelling, and far less informative, than last year’s Orange Tree collaboration between Brown and Strachan on The Promise, about the Balfour Declaration and the State of Israel.

But that play didn’t have the gargantuan presence of Warren Clarke, whose patriotically overpowering and war-mongering Winnie, with jutting lower lip and giant-sized Havanas, lies meatily half-way between Timothy Spall’s enjoyably coarse knockabout version in The King’s Speech and Robert Hardy’s upmarket, disdainful statesman in The Wilderness Years.