You have to be really getting somewhere to be able to claim a place as your own. The Stone Roses did it with their Spike Island extravaganza in 1990, a reunited Madness did it at Finsbury Park two years later. But whereas what those bands stood for (hedonistic Mancunian insouciance and nostalgia for north-London childhood respectively) was very clear, Blur's strength is their opacity. They are renaissance oiks. Their magpie assemblage of pop-culture calling cards - greyhound racing, track-suit tops, guest vocals from Phil Daniels and now Ken Livingstone - is designed to have something for everyone.
Like everything else Blur do, the location of this big show has been carefully calculated. Mile End park is a very depressing place - the myth of east London is much less evident here than the reality - and the sense of Blur revitalising a run-down location reflects a general feeling that their brazen cheek has given new life and confidence to British pop music. A couple of years back, people could say "pop is dead" and not be laughed out of town. Not now. Now callow young hopefuls are falling over themselves to follow Blur - and, less problematically, Oasis - through the Brit-pop breach into the mass market.
So what kind of Britishness is it that post-Blur bands like Menswear and Supergrass are celebrating? Back to Basics might have been disastrous in the political arena, but it has triumphed in pop. The core British values of short sharp tunes, laddish insouciance and shameless pilfering might have been triumphantly restated, but the innate conservatism of this project has been widely overlooked. The music-hall inflections of the Kinks and the Small Faces were nostalgic first time round; there is more than a hint of insularity about their wholesale readoption three decades on.
Watching Damon Albarn and Ray Davies singing "Waterloo Sunset" together on Channel 4's The White Room, pop music appears to be an unbroken circle. But it isn't an unbroken circle, as anyone forced to listen to anything the Kinks have done over the past 20 years will ruefully admit. It's the strange leaps and twists in pop's history that keep it fascinating. When Morrissey draped himself in a Union Jack at Madness's Finsbury Park show, he was justly pilloried. No one knew that he had merely made the old surfer's mistake of jumping on a wave before it was ready.
Within just a few months, Union Jacks were everywhere: a patriotic task- force was being assembled to repel the US grunge invasion. It was no accident that its leaders were united in their strong sense of place. Suede and Pulp both delved (and continue to delve) deep into their backgrounds - the suburban ghetto of Haywards Heath and "Sheffield, Sex City" respectively - in a bid to find something interesting to say about contemporary Britain.
People who don't like Blur tend to complain that they aren't real chirpy cockneys, but art-school boys slumming it. But such self-reinvention is a perfectly valid and respectable (not to say vital) Brit-pop tradition. It worked for the Clash and the Pogues, so why not Damon and co? You might as well crit-icise Rod Stewart (who, with a nice sense of timing, plays Wembley Stadium on Saturday, to three times as many people) for not really being Scottish.
The frightening thing about Blur is the thought that if you could take back from them what they have taken from others - the little bits of the Kinks, the Small Faces, David Bowie, the Jam and Madness - there might be nothing left. The same goes, in spades, for those who follow in their wake. Like Blur, straight out of Colchester, Oxford's Supergrass look to a sepia-tinted vision of London for their language and look (why else would they call their debut album I Should Coco)? The Small Faces went to school in Stepney Green, round the corner from Saturday's venue. They were revered by generations of students there for refusing an invitation to go back.
The people who are making the most exciting music in Britain today embrace an idea of themselves that goes beyond the theme tune from Minder. Enigmatic Mancunian Gerald Simpson, aka A Guy Called Gerald, has just released an album Black Secret Technology (Juicebox) that sounds like heaven would, if it was a motorway. His music manages to embrace American rap, Jamaican lovers' rock and European techno, without ever losing its distinctive, homegrown character. "It's British," he says, "it's definitely British, but it's how Britain has reflected on me."
Euros Childs, the charismatic 20-year-old singer of Carmarthen Bay prodigies Gorky's Zygotic Mynci, thinks so much great music made in Wales has been totally ignored that the very idea of British music has no value. Watching his almost frighteningly tuneful band play - Euros pounding away at a demented toy keyboard, bearded bass-players, trombones and violins meandering gleefully in and out of the mix - banishes any doubts that pop music has a future as well as a past. And looking to that future, the line between those who are happy to recycle the innovations of others and those who yearn for new sounds of their own grows ever more distinct.
! Blur plus guests: Mile End Stadium, E3, 0171 287 0932, Sat.