This had better be fucking worth it. I won't disclose how much I paid a man in a light brown coat outside the station for a ticket for this gig. But it was a lot of money. I decided to come this gig on a whim. In the past, I've fucking despised Coldplay and their whimsical, toe tapping sub-NAM bilge. To be frank, I thought ‘Shiver’ was the only decent track on their debut album. But their latest offering, ‘A Rush Of Blood To The Head‘ astounded me. It's several million light years on from ‘Parachutes’, and sounds as vitally now as anything I've heard this year.

So here I am, alone, queuing up outside the Forum, on a surprisingly sticky night, listening to someone in front of me talk about losing his virginity. The celebs are out in force. Dave Grohl, Simon Pegg, Steve Lamacq and countless others are parading around the Forum. And it's Coldplay they've come to see.

They amble on stage, Chris Martin looking every inch the rock star, dressed all in black, and strike up into the earth-shattering ‘Politik‘. The Forum's walls pound with the song's political resonance, and 'ver kids' all go ape on the floor. Martin's voice seems to have travelled a long way since it was spouting ‘Yellow’ to the happy indie clappers at Glastonbury two years ago. When he sings "Give me love over this" he sounds like some kind of hopeful prophet, preaching to his already converted army of gentle indie people.

Next follows a succession of ‘Parachutes’ songs. ‘Spies’ and ‘Trouble’ sound perfunctory, but only the aggressive, unrequited love blast of ‘Shiver" compares the emotional outpourings of the more recent songs. ‘Daylight’ showcases how tight Berryman, Buckland and Champion have become. Berryman's throbbing, Joy Division bass really hits home and as Champion bashes away like Keith Moon’s older, teetotal brother, Coldplay look like a complete band.

‘Don't Panic’ somewhat surprisingly, sounds fantastic, entirely due to the radical reworking the band have given it, and ‘Everything's Not Lost’ provides a special singalong moment for the whole audience. Even, cynical, bitter, moody old me feels impelled to join in. Just not too loudly, mind. I'll even stand for the cheeky, busked tribute to Ash Martin hammers out on his piano.

His acoustic version of one the band's strongest tracks, ‘Warning Sign’ is embarrassingly poor. A sumptuously orchestrated song on record, it becomes nothing more than a tired old strum-a-long when Martin croons it alone tonight. If anything, we’re reminded just how vital the three less famous ones are to their bands continuing success. All is salvaged however with the near groovy chug-a-long of ‘God Put A Smile...’. Chris' “honey honey‘”s seems to excite the female members of the audience in a way that ‘We Never Change’, say, could not.

‘Yellow’ is nowhere near as dull and predictable as it is when it's blaring out at some mid-thirties August barbeque, and in ‘The Scientist’, Coldplay have such an emotionally powerful song that if they're not careful, could soundtrack theirs, and our lives. It's stunning. Martin chimes away at his piano, eyes closed, every ounce of emotion in him is ringed out in his deliciously appealing voice.

The encores are similarly great. ‘In My Place’ and ‘Clocks’ in particular sound so complete, so timeless, so wondrously all encompassing.

As I leave the Forum, the sweat ringing off my Weezer T-Shirt, I try to work out whether tonight's fun and games have been worth the money. For all their 'bedwetter' faults, Coldplay have gone and changed my mind. From a Tesco's kiddies band that girls who send too many text messages like, they've become contenders, princes of the post-Britpop generation of guitar heroes, a serious, big gigs band.

I think Coldplay have opened my closed mind tonight.