Alan Bennett’s The Habit of Art seemed to me a masterpiece when I reviewed it at the end of last year at the National Theatre. This opinion was confirmed when I saw it out on tour this week, with different actors in the main roles but with the production team, including director Nicholas Hytner, exactly as it was in London. A fascinating study of the impulses behind artistic creation — specifically that of protagonists W.H. Auden and composer Benjamin Britten — the play has much to the point to say, too, about how the great are remembered, through the introduction of the character of Humphrey Carpenter who wrote lives of both men.

The three are brought together by means of a play within a play. What we see is the rehearsal — at the ‘National Theatre’, which might possibly bee confusing some of the Milton Keynes audience — of a play set in Auden’s shambolic cottage in Christ Church, Oxford, to which the poet had retired in 1972. The work of author Neil (Simon Bubb), Caliban’s Day stars the grumpily comic Fitz (Desmond Barrit, pictured) as Auden, the buttoned-up gay Henry (Malcolm Sinclair) as the composer and the dull-dog Donald (Matthew Cottle) as Carpenter, then with Radio Oxford, there to interview the writer.

Auden is at first unaware of this and hilariously mistakes him for rent boy Stuart (Luke Norris, pictured with Malcolm Sinclair), who is later to arrive for what some may consider a too near-the-knuckle discourse on the nitty-gritty of gay sex. Fitz himself objects to the sex, indeed to the warts-and-all portrait of this (literally) dirty old man, thus illustrating the usefulness of the play-within-a play device for disarming criticism as well as allowing Bennett to paint an affectionate picture of theatrical life and those involved in it. I was especially drawn, once again, to the character of stage manager Kay (Selina Cadell), diplomatic and delightful in ensuring the show will go on.

But it is, as before, the portrait of Auden that supplies the play’s richest pleasure. Desmond Barrit, one of our finest actors, outshines even Richard Griffiths, I felt, in showing us this rather frightening figure, while introducing a welcome, slightly Frankie Howerd-ish comic ingredient too.

Until Saturday. Box office: 0844 871 7652 (www.ambassadortickets.com/miltonkeynes)