When uncertainty beckons –  and especially when murder is afoot – it is always comforting to have a set of solid principles to cling to. Which explains why the more tightly structured the genre, the better (and funnier) any improvisation will be.

And so it goes with Murder She Didn’t Write. What we are essentially watching is a live action game of Cluedo, but with far more laughs. A smattering of audience suggestions (a setting, murder weapon, and the murder victim and culprit chosen via coloured post-it note) get things going with a huge sense of energy and good will.

Today’s scenario – The Case of The Purple Asparagus – sees a group of stock 1930s figures gathered for the funeral of Donald Trump (an obscenely popular audience suggestion) with all, of course, proving to be far from well. The character and plot details range far and wide, as only improv can do – one character shifts from a vicar to an ex-wife, ex-burlesque dancer, lover of the victim and…well, that would be telling. It’s the kind of thing that can fall utterly flat in the wrong hands, but Degrees of Error know exactly what they’re doing. The actors look like they’re having a fantastic time, flinging themselves into flashbacks, false accusations and passionate cliches (as well as trying very hard not to corpse one another, and sometimes failing adorably).

As well as keeping the makeshift plot running along, the cast also manage to slip in a large number of topical gags and true-life Trump references. Some sadly sail over the audience’s heads but others (walls made from folding screen doors and a supposed son unmasked when he is revealed to be wearing tiny prosthetic hands) really hit. It all ends up making a surprising amount of sense as we gather for the denouement, and crucially, it feels almost effortless. A perfect respite for the ‘little grey cells’, as Poirot might say.