By William Schomberg and Georgina Cooper

LONDON (Reuters) - Piles of punk music memorabilia went up in flames on a river barge in London on Saturday in a protest against the way the once rebellious genre has been subsumed into mainstream culture.

Joe Corre, son of former Sex Pistols manager Malcolm McLaren and designer Vivienne Westwood, set fire to clothes and paraphernalia he valued at between 5 and 10 million pounds ($6.2 million - $12.5 million), on the 40th anniversary of the band's debut single "Anarchy in the UK".

Standing in front of flags bearing the names of global corporations, Corre also burned firework-stuffed effigies of Prime Minister Theresa May and her predecessors David Cameron and Tony Blair, dressed in Sex Pistols clothes.

"Punk was never meant to be nostalgic," Corre said, addressing a crowd of around 100 people on the bank of the River Thames in the affluent Chelsea area of London.

"Punk has become another marketing tool to sell you something you don't need," said Corre, who himself co-founded lingerie brand Agent Provocateur.

He directed his "Burn Punk London" protest at a celebration of punk music backed by the Mayor of London and the British Council, called Punk.London.

Corre's punk collection, which he began burning a few days ago and will continue to destroy over the coming weeks, includes rare Pistols recordings.

Sex Pistols guitarist Glen Matlock told Sky News that Corre's protest was "dopey".

"I want to paraphrase Monty Python - he's not the savior, he's a naughty boy. I think that Joe is not the anti-Christ, I think he's a nincompoop," Matlock said.

(Reporting by Georgina Cooper and William Schomberg, writing by Andy Bruce; Editing by Mark Trevelyan)