IN 1990, Alan Bennett, arguably the most prolific of British authors of performance material, published a slim memoir titled “The Lady In The Van”. 

In Nicholas Hytner’s film, Maggie Smith plays that Lady and Alex Jennings plays Bennett. Miss Shepherd parked her clapped-out van in the Camden Town street along which many of Britain’s leading twentieth century creative people also lived. When the council made the street “no parking”, she persuaded Bennett to let her park the van permanently in his drive. She stayed for 15 years.

Miss Shepherd is a don’t-mess-with-me eccentric, making her a fun theme for performance. Smith’s having played her and Margaret Fairchild on stage and radio with Bennett, it’s no surprise that her film portrayal is pitch perfect. Bennett got to know Miss Shepherd in sometimes awkward proximity – she hadn’t had a bath for several decades and the nearest lavatory was on his first floor.

The verity of Bennett’s screenplay is close to unchallengeable, hardly surprising since he’s its real-life other principal character. The locations are exactly where the book’s events took place. If some of its moments are inventions, so what? It’s also Bennett’s story, to embellish however he wishes!

With the wit for which he is famous, Bennett writes brilliant yet brutal comedy that, in the film, doesn’t resile its in-your-face qualities. Nuns feature in Miss Shepherd’s history with scant credit. Why is somebody blackmailing her? The answer invites people of goodwill and sensitivity to weep a little just in time for a mawkishly sweet finale. The reason for calling her Margaret Fairchild is indisputable. But you’ll miss it if you blink!

At Palace Electric and Dendy from March 3.