By Mark Savage
Entertainment reporter, BBC News
Hundreds of U2 fans have queued overnight to meet their rock heroes, who were in London to launch their official biography.
After braving a stormy night on the streets of central London, 100 fans managed to secure tickets for the event, joining 150 competition winners from the band's website.
"My boyfriend came down just after midday yesterday," said Sunny Kang, 26, from London. "I met him at six o'clock in the evening and took over and I've been here ever since.
"It was pretty rainy but there was a good group of us, and I managed to get about half an hour's kip which was more than anyone else got."
U2's appearance was only announced on Thursday, and many of the band's devotees dropped everything to dash to London.
"It was a last minute rush to get the flights down here from Glasgow," said Jo Taggart, who turns 29 on Saturday.
Ian O'Flynn and Jo Taggart won tickets to the event on U2's website
"This is my birthday present for myself."
The Irish group were due to arrive at book-sellers Waterstones at midday but, in keeping with time-honoured rock tradition, they kept fans waiting for another hour before making an appearance.
Undeterred, the crowd gave them a loud cheer as they emerged from a lift surrounded by security guards.
But before the band got down to the business of meeting their public, they had to face the press.
Lead singer Bono, who has been a vocal campaigner for third world debt relief, was asked if he planned to give up political activism.
"I would always rather be with a band in a rehearsal room," he told the BBC.
"The activism I do because I can, and I should. What else am I going to do with this rather ridiculous thing called celebrity?
"Hopefully we'll put ourselves out of a job... then pop stars and sports stars and rock stars can stay in bed like they'd really like to."
250 fans attended the event, to be repeated in Dublin on Saturday
The 46-year-old singer was more inclined to talk about his group than his high-powered meetings with George Bush and Tony Blair.
He said they had kept working for so long because of "a fear of turning
into your worst nightmare.
"In the Seventies, when we grew up, we saw bands lose it, saw it all go to
"With our band we think we have to justify our existence."
The stadium rockers' book, U2 By U2, puts all that hard work into perspective.
Lead singer Bono talked and joked with fans at the event
Released on Friday, it is a 350-page history of the group's 30-year career.
Compiled from more than 150 hours of interviews with the four bandmates and
"fifth member", manager Paul McGuinness, it also includes many rare photos from the group's personal archive.
It took two years to put together, but on Friday Bono said that he hadn't enjoyed the process.
"I hate it. It's like pulling teeth," he said. "I'm much more interested in the future than the past.
"But this year we thought it was time to take a deep breath, accept we've
done some interesting stuff, wrap it up in a bow and put it out there."
Having endured their press commitments, the band finally got round to meeting their fans.
Sunny Kang was first in the queue, and received a kiss from The Edge in recognition of her long wait.
Close behind her was 38-year-old Sean Meek, who had travelled 300 miles from York to meet his idols.
"It's been worth everything," he said. "For 21 years I've been a fan of theirs. I get to meet them and they're just down-to-earth.
Londoner Sunny Kang was first in the queue to meet the band
"It's just like speaking to my brother or sister. No egos whatsoever.
"I'm going to be awake for the next three days from the adrenaline. It's like being at a concert."
U2 are currently recording their twelfth studio album with Beastie Boys and Red Hot Chili Peppers producer Rick Rubin.
On Monday, they perform at the re-opening of the Louisiana Superdome, which was the scene of some of the worst suffering caused by Hurricane Katrina last year.
They will play a version of The Skids' 1978 single The Saints Are Coming with punk band Green Day.
The song will also be released as a single for The Edge's charity Music Rising, which helps replace instruments lost in Hurricane Katrina.