British TV chef Jamie Oliver is to take his food campaign to the Olympics in a bid to ban big junk-food companies, such as McDonald's and Coca-Cola, from sponsoring the event unless they meet nutritional and ethical standards.
"It's probably my most audacious thing I've dreamed up. And I don't know if I have what it takes to pull it off," he said.
He said he was depressed the only food available inside London's Olympic Park in 2012 was McDonald's, Coca-Cola drinks or Cadbury snacks.
"Nobody can be proud of the London Olympics from that perspective. There was an opportunity to shout about how amazing and diverse British food culture is. But you didn't get to see that."
He has started trying to raise 100 million ($216 million) to create a kite mark that could be used by any food company to show they had reached certain standards for nutrition and ethical sourcing.
His ambition is that only firms that earn the kite mark will be allowed to sponsor or supply the Olympics, targeting the Tokyo 2020 tournament.
"More than anything - and forgive me if I am being romantic - but in our lifetime at the Olympics, which is the biggest theatre of all time, I want to see something with goodness at its heart on its billboards."
He said his team had spoken to the International Olympic Committee (IOC), which was receptive to the idea. "I want to get in the game as a premier-league sponsor. I don't want to fight with any of the other advertisers."
His attempt to reform the IOC's reliance on money from junk food firms - McDonald's has been part of the Games since 1976 and Coke has been a backer since 1928 - is his latest campaign to improve children's nutrition.
His TV series about school lunches was broadcast 11 years ago, and his controversial call for a sugar tax on fizzy drink was announced this week.
An outright ban on McDonald's or Coca-Cola at the Olympics, he said, was not his goal. But he hoped the companies would see the kite mark as an opportunity to improve their own standards.
He highlighted McDonald's British arm, which reformed its sourcing policy a decade ago.
"You have to ... say 'well done' to big businesses when they do good. And McDonald's probably props up the British organic milk industry, 100 per cent free range eggs, British and Irish ground beef."