During the evening, Robbie Williams will allude to his dependence on anti-depressants and send up his inability to find a partner. There is a mania about the savagery of his self-satire, his compulsion to disclose. He is the archetypal sad clown, loved, perhaps, because we like to be reminded that success does not equal happiness.

Williams's genius is his mix of vulnerability and arrogance. Sometimes he is the jealous lover, questioning the cheer that goes up when he mentions other artists: Justin Timberlake (whom he admires) or Ronan Keating (whom he sends up perfectly).

Sometimes the endless braggadocio (he's got a very big tour, you know) palls, though he does deliver brilliantly contemporary pop music, including his best songs: No Regrets (very Pet Shop Boys), Me and My Monkey (gorgeous mariachi brass over a lacerating shaggy-dog story) and the manic attention seeking of Let Me Entertain You.

Bizarrely, he is briefly joined on the piano by Max Beesley, well-appointed but little-known Brit actor and former Mr Scary Spice, who, even more bizarrely, doubles as tour percussionist. Apparently they spent time together in LA when, Williams says: "Max was out there carving out his career and I was just . . . out there."

Williams hams through Mr Bojangles like he doesn't know the difference between Sammy Davis Jr and Andy Williams, but wrings a good deal of pathos from One More for My Baby.

The band swing back in for She's the One, but it makes no difference how many people crowd the stage, we only have eyes for one person, and it isn't Beesley. During a monumental Kids, Williams deftly removes his trousers and two colossal video screens afford us a lingering crotch shot.

Williams comes very near to dwarfing this enormous space. By the end and Angels (what else?), he is clearly high on the applause. But you can't help wondering what will happen when it stops.