This is a Meryl Streep film about a bad singer: like Mamma Mia but with Streep in the Pierce Brosnan role.

In 1944 New York, Jenkins (played by Streep) was a wealthy society lady who, alongside her British thespian husband St Clair Bayfield (Grant), was a vigorous patron of the musical arts. She also sang, hilariously badly, in concerts for all her insufferable theatre-type friends, who sycophantically told her she was simply marvellous.

Theirs was a strange marriage, with Bayfield slippping off each evening to the flat he shared with his lover (Ferguson).

But he is devoted to FFJ, and carefully manages her musical career, trying to ensure that nothing penetrates her fantasy of being a great singer, insisting that tickets for her performances be sold only to “music lovers”.

He is also spends his time warily on the watch out for other people trying to slip their way into her affections, and her will.

The film maintains a fine balance of frivolous poignancy: it’s funny, while being sympathetic to the delusions and desperate calculations the characters make.

Jenkin’s devotion to singing is presented as an expression of her deep love for music.

But the film could just as easily be seen as confirmation that the high arts, your theatre and opera, are a great big self-sustaining racket where well-connected mediocrity is elevated by the influence of rich patrons. In this way, Florence is both Saatchi and Tracy Emin.

Padded up to resemble Dame Edith Evans and Margaret Dumont, Streep is a hoot in the main role but it is Grant’s film.

Initially his character is rather ambiguous, but after test screenings the film was re-jigged to make him more sympathetic and I’d guess it works much better this way. Grant doesn’t need to have it spelt out; after all those years in romcoms he is able to convey the wincing compromises of his character effortlessly.

The script has him say: “I was a good actor but I was never going to be a great actor”

But when he taps into his dark side, he’s terrific.

His Bayfield is a magnificent study in conscientious, heartfelt poncing.

Rating: 4/5 stars.