Here is a sampling of what they had to say:
Benedict Nightingale of The London Times: "Together, Stephen Daldry and Lee Hall have concocted a piece that's tougher, bolder and, as my tear-ducts can attest, more moving than its admittedly admirable celluloid precursor… Thanks to Peter Darling's inventive choreography, we get dances of police and miners that start in Keystone style but get more menacing with the introduction of batons and clubs, and end with a stupendous number in which the cops become a terrifying wall of riot shields against which Billy flutters and bangs like a distracted moth…. If there is a disappointment, it is Elton John's music, which begins promisingly, with a church-like paean to camaraderie, but never seems either tuneful or original."
Nicholas de Jongh of The Evening Standard: "Billy Elliot The Musical, based upon Stephen Daldry's classic movie, is just irresistible. It catches you--or at least me--in its fervent grasp, and pins you down with all the artfulness of a vintage seducer, right to the misguided, sentimental finale… This is an evening which throws a fierce political punch as well as an emotional one. No modern musical has struck such rebellious, old Labour, workingclass conscious notes… Stephen Daldry, always at his best on the grand scale, deftly marshals a throbbing mixture of angry miners, threatening policemen and little girls in tutus--all singing. Ian MacNeil's versatile designs set the changing scenes."
Charles Spencer of The Telegraph: "Billy Elliot strikes me as the greatest British musical I have ever seen, and I have not forgotten Lionel Bart's Oliver! or Andrew Lloyd Webber's Phantom of the Opera. There is a rawness, a warm humour and a sheer humanity here that is worlds removed from the soulless slickness of most musicals… Elton John has written a wonderful score that ranges from folk to hard rock, from razzle-dazzle show tunes to soaring anthems of human solidarity and defiance. Hall's vivid and, be warned, expletive-filled dialogue turns on a sixpence from gamy humour to sudden depths of pathos, and his lyrics are sharp and evocative. Daldry's production, with a deliberately scruffy design by Ian MacNeil that vividly captures the period and the poverty of the characters' lives, is blessed with great energy."
Paul Taylor of The Independent: "There are all kinds of problems to be surmounted in adapting Billy Elliot into a stage musical. But Stephen Daldry's exhilarating production has some brilliant solutions up its fluffy pink tutu… Peter Darling's witty and constantly inventive choreography has the answers to another tricky difficulty. There's an uplifting scene where the whole world seems to turn into a dance class. With the police and the miners breaking into the unconscious patterns of Northumbrian folk dance and the children surreally swapping round the different types of helmet, this elaborate routine has the humane effect of showing how these two conflicting groups of men share the same working class culture."