If there is a strong commercial bent in the National’s production of Michael Frayn’s play which will tour to major theatres next year, it is nothing to be ashamed of.  Noises Off is one of the funniest plays of the last 25 years, almost classically neat in its construction, and giving the lie to the contention that plays about the theatre are not successful. This is even more about the nuts and bolts of the theatre than usual in pieces of this type, showing both front and backstage of a touring production called Nothing On, starting with its production date at Weston-super-Mare and ending with its stormy conclusion at Stockton-on-Tees. Oddly enough  it has not dated since its premiere 20 years ago. There are still tours of sub-standard farces featuring randy young men, willing young women and comic servants. And I dare say that some of them, at least, are beset with the same problems as Nothing On. The leading lady has a stake in the show, the director regards this particular job as beneath his notice, any bottles of spirits have to be hidden from the elderly character actor and the show is being run by an untried stage management team who also have to understudy all the roles.

We see the first act of Nothing On three times, once from the front as a chaotic dress rehearsal, once from the back as everybody is quarrelling with each other a month into the tour, and again from the front at the catastrophic final performance in which sheer malice gets the upper hand with immense comic effect. A play such as this requires not only energy but almost miraculous comedy timing. which director Jeremy Sams ensures that it receives from a cast that has no weak links. Every performance is cherishable, from Patricia Hodge as a would-be grande dame who has spent her life playing comic chars, to Selina Grlffiths and Paul Thornley as  the perpetually harassed SMs. Here too are Peter Egan, bearded like Peter Hall as the director, Aden Gillett and Natalie WaIter as the eager young couple, Jeff Rawle and Susie Blake as the tax-evading owners of the country house in which it is set, and Christopher Benjamin as the burglar reduced to petty pilfering after tackling bullion vaults in his time.

Almost the greatest masterpiece of all is Robert Jones’ wonderful traditional set, the mock opulence of the front contrasting with the tattiness behind the scenes.