The theatre has been quarantined, all the exits are guarded and nobody is allowed to leave. Why, even the stage cat has been deprived his nocturnal prowl.

Not because of the coronavirus (though given its rapid escalation, mass gatherings in artistic, sporting and public arenas are likely to be curtailed), but due to the sudden death of Jessica Cranshaw (Nia Jermin), leading lady of the Broadway-bound musical Robbin Hood, whose questionable talent can best be inferred from director Christopher Belling’s (Samuel Holmes’) catty remark upon hearing her pulse is refusing to still: “That’s the first time she’s ever kept a beat.”

Step forward (or rather step-ball-change into the spotlight) amateur thespian and professional sleuth Lieutenant Frank Cioffi (an engaging, endearing and fine-voiced Jason Manford) who in addition to solving a brace of murders (“Three if you count the integrity of musical theatre,” hisses Belling) takes it upon himself to salvage the show’s closing number In The Same Boat which has undergone more rewrites than a Harvey Weinstein’s nondisclosure agreement.

Though not a patch on Kander and Ebb’s earlier triumphs Cabaret and Chicago, the aptly named Curtains, which premiered two years after the curtains closed on Ebb’s long and distinguished career in 2006, is nonetheless an enjoyable romp.

A cross between Noises Off and Columbo, it takes a while to grab the attention and quicken the pulse (the opening numbers lack what Cioffi instills into the flagging finale “vim”, which is more to do with the writing rather than Paul Foster’s drilled direction). But when the bullets start flying and the wisecracks start pockmarking the fourth wall (mostly, it has to be said, catapulted from the comedy chops of Samuel Holmes’ Coward-esque Belling), the boat of the show unlike the boat in the closing number rises fast.

The terror and thrill of performing is touched upon, as is the yin and the yang relationship between composer and lyricist. Indeed, the one poignant moment, no doubt inspired by the passing of Ebb, concerns Robbin Hood co-lyricist Aaron Fox (Ore Oduba) lamenting the loss of his songwriting partner Georgia Hendricks (Carley Stenson) with the blunt admission, “I miss the music, I miss my friend.”

Though in the words of the ballsy producer Carmen Bernstein (played with great gusto by Rebecca Lock): “The show must go on.”

Peter Callaghan