There can be few greater challenges in showbusiness than the title role in Bill Kenwright's hugely popular musical The Roy Orbison Story, writes Chris Gray.

Dare one imitate the inimitable? Invite a comparison with the incomparable?

I am not speaking in terms of looks, which in the Big O's case were the least important part of his appeal (actually his early managers considered him so plug-ugly they actively kept him out of the public eye). No, anyone can slick back dyed jet black hair and don the trademark Ray-Ban sunglasses; but very few can reproduce That Voice.

One who emphatically can is Damien Edwards, whose uncanny ability to imitate the Texan-born star is captivating packed houses this week at the Milton Keynes Theatre. I can pay him no greater compliment than to say that during his performance of certain great songs I could close my eyes and travel back to the Orbison performances I feel privileged to have seen the last at Oxford's Apollo Theatre in March 1977.

On Oh Pretty Woman, for instance, with which the Big O generally finished his act, we can once more savour the famous growl before his plea for "mercy", and on In Dreams - perhaps the greatest of Orbison's songs - he rises magnificently to the formidable challenge of the piercing falsetto in its closing bars.

The success of his performance owes much, of course, to the musical arrangements of the director Keith Strachan, and their near-flawless execution by a six-strong band under musical director Kevin Oliver Jones.

The book by Shirley Roden and Jon Miller provides a lucid account of Orbison's life, successfully avoiding mawkishness over it sadder aspects the death of his beloved wife Claudette (Helen Fisher) in a motorcycle accident, the loss of two of his young sons in a house fire, his own ill-health and early death.

We also see the artist's creative life set against a wider musical background, from his early tours with Patsy Cline (Caroline Deverill) and Bobby Vee (Klaus White), through his sixties' heyday as a rival to the Beatles, to his final glory days with the Travelling Wilburys.

On the way we meet many of his fellow stars who are impersonated with varying degrees of success. Kludo White gives us a fine John Lennon (some compensation for the hash he makes of Bruce Springsteen's Born to Run); Jaison Beeson revives memories of one-hit-wonder Arthur Brown with Fire ; Andy Pelos struts to amusing effect as Mick Jagger on Jumpin' Jack Flash; and Ms Deverill makes a moving appearance as Dusty Springfield, on I Close my Eyes and Count to Ten.