London Marathon director Hugh Brasher has eased fears the race could be disrupted by protests after receiving assurances from Extinction Rebellion.
The group has vowed to protect the event on Sunday from disorder so the 45,000 runners can compete.
The World Snooker Championship was disrupted on Monday after a Just Stop Oil protester climbed on a table and covered it in orange powder during a game between Robert Milkins and Joe Perry.
Brasher was due to hold talks with Just Stop Oil on Wednesday afternoon in the hope of avoiding further protests in the capital but has been given assurances by others.
“I’ve come from a meeting with Extinction Rebellion, they will be uniquely asking all their participants to help guard the London Marathon,” he said. “To do something which is unique in their history, to protect what is one of the crown jewels of British sport.
“We have been talking to Extinction Rebellion for months. They have been very clear they are in a new phase of wanting to engage the general public in a different way.
“It was not Extinction Rebellion at the snooker, it was Just Stop Oil. I’m having conversations with Just Stop Oil, I hope in those conversations they will be giving the same assurances.
“We do mitigate for disruption and have done for years. There are numerous mitigations we put in, we do that working with the police, the Royal Parks, Westminster, the Mayor.
“I won’t say what they are. We don’t say what we are doing, but we have a raft of additional mitigation measures we are putting in to this year’s event.
“The London Marathon is unique, we run for clean air, that is so important in what we do.
“We’ve not traded anything off, all we are doing is having conversations and asking if we can work together. So far everyone has been incredibly positive in that manner.
“I will be asking them to help and protect the marathon because of the good it does in society.”