It seems a sin that Maggie Smith’s performance in Lady in the Van — surely one of the very greatest in living memory — be showcased in as drab-looking, poorly directed, and stagily-structured film. Alan Bennett — Mr. Modest, Mr. Timid and Mr. Professional Yorkshireman — also turns out to have an ego the size of the Twin Towers, appearing in four different guises throughout the film, two as himself doubled by excellent impersonations from Alex Jennings, one as one of the Alex Jennings Bennetts appearing in ‘Talking Heads’ at The National, and yet one more time, as the real Alan Bennett coming to greet the fictional Alan Bennett as he’s shooting a film about Alan Bennett, like the coy milking of applause by an ageing diva, half-hiding behind the fan of her previous celebrity, saying ‘no, please, little old me?’ with one hand and urging the audience to amp up the applause with the other. It’s shameless.

There are lots of laughs, almost all from Smith, and lots that is unspeakably bad, almost all due to Hytner, who doesn’t seem to know the basics of using a camera, or lights or sound or editing; and who uses the device of the two Alan Bennetts speaking to each other – an old trick that is hoary now even on stage – without any imagination as to sight or sound on film and is a device that holds up the narrative. Also, there’s so much reading of narration (all timid Bennett’s of course as read by modest Bennett) you sometimes wonder whether the filmmakers remembered they were making a movie. Maggie Smith, star that she is, survives, rises above all this naff incompetence, and in my humble view gives the finest comic performance on film since Goldie Hawn’s Private Benjamin, in spite of the director who doesn’t know how to showcase her, and in spite of a writer who tries to push her out of the picture to make room for himself.

The film rewards viewing as an embodiment and prime exemplar of the many negative qualities historically ascribed to British cinema and as a lesson to future filmmakers in what to avoid.

José Arroyo