Samuel West programmed this production of Caryl Churchill’s taut, 50-minute two-hander about human cloning in 2006 to run for three weeks as part of his second season then in charge of Sheffield Crucible. He, his father Timothy West and director Jonathan Munby have been wanting to do it again ever since, dependent on the right venue. And they’ve found that in the Menier Chocolate Factory which, for the first time, has been configured in-the-round, replicating the dimensions of the Crucible.

The seating arrangement - as well as the casting of a real-life father and son and other directorial decisions - makes this feel like an entirely different, and much more intimate, piece than the play’s world premiere production, which starred Daniel Craig (in his last London stage appearance before international fame as James Bond) and Michael Gambon, directed by Stephen Daldry at the Royal Court in 2002. Though similarly slick and thought-provoking, the enduring ideas left with me by the original centred on the ethical and identity quandaries thrown up by the situation, which begins with a thirty-something man confronting his father after discovering that he’s just one of “a number” of sons resulting from a cloning cock-up.

With the Wests, the human drama is brought fully to the fore, and you come to care much more about this particular father and the painfully awkward relationships with his various sons, all played by his real son, who masterfully distinguishes three physically identical men with a change of jackets, demeanour, accent and attitude. There are also hints, obfuscated by lies and half-truths, of the family tragedies that led to, and resulted from, the cloning, and a very powerful argument for the importance of nurture over nature.

The concentrated mood is enhanced by Paul Wills’ simple design – just an armchair and sidetable, a copy of the Daily Mail opened to the puzzle pages, overhung by a grid of test tube stalactites – and scene transitions in which West senior is spun round to the four corners to the mechanised sound and sliding blue light of a photocopier.

The beauty of the play and the production aside, the chance to witness the generational baton being passed – and so adroitly – in this revered family of actors is unmissable.

- Terri Paddock

NOTE: The following FIVE-STAR review dates from October 2006 and this production’s original run at the Sheffield Crucible.

Everything about Sheffield Crucible’s production of A Number is small-scale. The play lasts less than an hour and requires a cast of two, while the in-the-round production is played out on a tiny square of stage, with minimal furniture and props. However, the impact of this superb production is out of all proportion to the slender resources.

Recently Sheffield Theatres have done more than most to remind us that, if you want intelligent and challenging drama, it’s no bad idea to turn to Caryl Churchill. A Number again demonstrates her ability to explore the limits of naturalism and to cloak moral and philosophical debate in powerful theatrical utterance.

“A number” is the first line of the play. Youngish Bernard, a palpably decent fellow, is taking a problem to his crusty middle-Englander of a father. He has found that he has been cloned from the same source as “a number” of other men, though Salter, his father, the sort of dogged chap you believe implicitly, insists that Bernard was born normally and the others have been cloned from him. Salter even talks of the exact sums to be won in litigation for a sort of identity theft.

However, despite appearances Salter is not good at truth and, as one fiction after another is discredited, Bernard Mark 1 appears, the original of all the clones and the son that Salter gave away 35 years before.

A Number is not a play about the moral dilemma of cloning. Churchill has bigger fish to fry: identity, individuality, nature versus nurture, even a Jekyll-and-Hyde dualism. After tragedy and angst comes a scene with a disarmingly eager Mathematics teacher, one of the clones, who cannot provide any evidence of individual identity that Salter can recognise – and yet he is, apologetically, happy.

Jonathan Munby’s apparently effortless production begins with a tour de force of naturalistic acting, father and son in a beautifully paced exposition via fractured phrases, overlapping lines and sentences completed by each other. Timothy West moves from this troubled, but light-on-its-feet, dialogue to moments of granite stillness and a desperate search for his son’s (any son’s) identity, all with absolute conviction. Samuel West’s assumption of the roles of the three sons is, by any standards, remarkable, with his chillingly possessed Bernard 1 sandwiched between two gentler souls, one tormented, one blithe.

With an almost non-existent set, Hartley T A Kemp’s evocative lighting and Olly Fox’s music do much to complement a production rich in intelligent detail and perfectly judged acting.

- Ron Simpson