One of the earliest of George Bernard Shaw's plays, Mrs Warren's Profession -- completed in 1894 -- was not publicly performed for another 31 years.

Why so? Because the 'profession' under consideration was the oldest one, so-called, and such a subject was not deemed suitable for mention on stage, as in polite society.

That prostitution thrived -- was utterly accepted yet unacceptable -- was itself one of the major themes of Shaw's gripping play. Ever keen to expose hypocrisy, he found here a glaring example of it.

This enjoyable production, directed by Sir Peter Hall, at the Oxford Playhouse comes hotfoot from the West End. There have been changes of cast -- chiefly Twiggy Lawson's substitution for Brenda Blethyn in the title role and Hannah Yelland taking over from award-winning Rebecca Hall as Mrs W's bluestocking daughter, Vivie.

The latter performs with great distinction, perfectly conveying the horror of a young woman who discovers that her Cambridge education has been funded by the proceeds of prostitution in a chain of brothels run by her mater.

On top of this she must fight off the amorous advances of Sir George Crofts (Jeremy Clyde), the middle-aged rou who is her mother's partner-in-crime, while coming to terms with the possibility that her chirpy young boyfriend Frank (Ryan Kiggel) might be her half-brother. That's because earlier in life Mrs Warren had a fling with Frank's father, the Rev Samuel Gardner (Mike Burnside) -- now the snooty (and boozy) incumbent of the parish where Vivie has her summer home.

But what of Twiggy? Having branched out, as it were, from modelling into theatre (via a number of roles in musicals), she can hardly be said to possess all the attributes of a classical actress. Her voice, for instance, lacks much in the way of variety -- veering between the nasal and the irritatingly shrill.

As might be imagined, she is at her best when -- the true nature of her employment having been revealed to Vivie -- she drops the pretence of being the grande dame and allows her Cockney roots to show.

But she remains eminently watchable throughout the drama, clearly showing the charm of a character able to win the admiration of such an all-round good egg as the architect Mr Praed (Benedict Blythe) -- perhaps the only really pleasant character in the whole piece.

The action proceeds at a cracking pace under Sir Peter's steady hand, but only a director of his eminence, I think, would dare to leave an audience sitting for so long between scene changes.

The play continues at the Oxford Playhouse until May 10.

CHRIS GRAY