Added to which, it's not clear what Franklin (an anguished Mark Umbers) has done that is so reprehensible, beyond making money from films, moving to LA and deserting clingy Mary (the superbly vengeful Jenna Russell) and his old scriptwriting mate Charley (Damian Humbley). This is hardly moral turpitude on a grand scale, even in liberal New York in the 1970s. 

Sondheim's second-best is however pretty good, enlivened by sharp lyrics and an attempt to answer that lurking mid-life question: "How did we get from there to here?" Damned if I know. But verily, it rolls along. 

For an altogether more worrying mid-life decline, Hjalmar Söderberg's classic story of obsession and murder in a small Swedish town, Doktor Glas, deserves a eulogy. So does the Wyndham's for trusting West End audiences with a century-old Scandi-monologue, albeit with surtitles. 

Krister Henriksson is the provincial doctor whose empathy for a female patient exposes the seamy side of life in respectable Sweden in 1905 — the same year that Gorky had more explosive things to worry about in provincial Russia.

Abortion, adultery and the justifications of murder are the moral conundrums, and Linus Fellbom's extraordinary lighting reflects Söderberg's preoccupation with the impact of the seasons and light on moods and morality. It's a haunting, mood-altering hour-and-a-half of something different from anything else on the London stage. I did, however, receive an anguished text from a friend after recommending it, which read: "Hang on, it's in SWEDISH." When it comes to critics, like insurance policies, do read the small print.