911 ** Wembley Arena

There are conventions in this kind of show that 911 and their fans stuck to as meticulously as if this were a religious service. The boys strutted through their singles, the pre-teens squealed; the boys introduced their band and bantered incomprehensibly, the pre-teens squealed louder; the gamine Lee Brennan did a few exaggerated pelvic thrusts and the teens nearly fainted with lustful excitement. One girl clutched a banner screaming Lee Hot Sexy Devil, sawn-off lightsabres flashed through the auditorium like comets, and every one threw their arms up during Wonderland with a unity that was oddly thrilling.

It was all blissfully bland. And then a bizarre thing happened. Just before the second verse of their only number one song, A Little Bit More, Brennan did the obligatory thing of holding out his microphone for the audience to sing along, and was greeted with absolute silence. Not only was no one singing, no one was making a peep. The quiet was eerie and frankly embarrassing, and 911 didn't even cover it up by singing themselves. The boys had entered the twilight zone: they had flummoxed the audience.

It wasn't the only time it happened. Half way through they engaged in some childish theatrics, a little playful time travel. They popped back to the 50s to cover Eddie Cochrane's C'mon Everybody, then zipped to the 80s. But instead of plumping for the safe option, their insipid cover of Rick Astley's Never Gonna Give You Up, they went for MC Hammer's You Can't Touch This. Funny, that, because half the audience hadn't been born when the song was released, and it fell flat.

Suddenly, everything was bemusing. The sound quality was appalling, as if the soundman was trying to disguise the weakness of their shrill voices with distortion. Their cover version of More Than a Woman made me long to be watching the Bee Gees, an uncomfortable feeling I hope never returns.