His admirers can be forgiven for fretting about what on earth he will do next. One minute Mandy Patinkin is patrolling the mean streets in the TV series Criminal Minds, the next he is twisting that curious voice around a Sondheim lyric or playing Prospero on the boards in Manhattan. His volatility is part of his appeal, of course, but his sheer intensity can make a couple of hours in his company seem as gruelling as a route march across the Catskills. Twelve years ago, when he played the Almeida, he found a way of tempering the idiosyncrasies with a measure of self-discipline. This time he lets it all hang out.

In a way, it is like watching a two-hour battle between Patinkin the actor and Mandy the singer. He brings extraordinary dramatic energy to everything he touches - his treatment of Sondheim's Being Alive is nothing short of mesmerising - but even his most devoted fans will find it hard to get through the weird juxtapositions, the Al Jolson impersonations and the raucous humour without a certain amount of gnashing of teeth.

Patinkin once said in an interview that he was not sure whether he was a tenor or a bass, or what his high and low notes were. He still seems uncertain, generating a sense of recklessness that is exhilarating in small doses but debilitating over the long haul. He packs in so many anecdotes, asides and jokes that you feel dizzy well before the climactic sequence when he delivers Take Me Out to the Ball Game and God Bless America in Yiddish. He is capable of starting a song in a swaggeringly masculine frame of mind and ending it in a mincingly feminine register. Sometimes it works; sometimes you feel as if you are watching Humphrey Bogart auditioning for Bugsy Malone.

There was drama even before the opening night when Patinkin's long-time collaborator and accompanist Paul Ford had an emergency appendectomy in New York. Into his shoes, with only minimal time for rehearsal, stepped the young pianist Ben Toth, who does an heroic job of following his partner on every step of an epic journey, from the chamber ambience of the extracts from Sunday in the Park with George to the folksier cadences of On the Atchison, Topeka and the Santa Fe.

Inevitably, there were false starts and one wag in the auditorium suggested that a phone call to Sondheim himself might help Patinkin to deal with a particularly severe memory lapse. Still, the second and third takes added to the aura of unpredictability. Patinkin is never going to be your conventionally sleek purveyor of showtunes.

To Jan 18, box office: 0870 0606623

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