Il Nuovo Postiglione - Climate protesters launch four-day mass action in London

"This is about broadening the invite and bringing far more people in far more groups on board," said Clare Farrell, the co-founder of the group known as XR.

"For a lot of people, going on a march like coming to a picket is a first step," she told AFP, promising targeted "non-violent civil disobedience".

XR has in recent years caused huge disruption, hitting roads, airports and other public transport networks with direct action protests against climate change.

But in January it called a temporary halt to its high-profile demos, and instead promised to mobilise huge numbers against what it sees as government inaction against global warming.

The group hopes that 100,000 people will gather outside parliament this weekend and so far has said it has seen 30,000 people register their interest.

It hopes that 40,000 to 50,000 people will attend "The Big One" event, which coincides with the London Marathon on Sunday.

Discussions have been held with race organisers to reduce disruption.

Julia Hailes, a climate activist for 35 years, was among those who set up stalls in central London on Friday.

"People are becoming aware... that we are facing a devastating future and we have a window of opportunity where we need to do something about it," she said, wearing a crown of plants on her head.

"The Earth is dying. We have to stop this."

Her son, Connor Bryant, 28, said his children and great-grandchildren will be more affected by climate change.

"So action is in some ways so important for me to feel that I'm doing what is required to protect everyone I will ever love," he added.

More disruptive, drastic action was "inevitable the closer we get to the fire", he said.

Protester Lisa Milne said she was hesitant about taking action that caused "friction" with the public.

"I was happier to come along this time and join in and show support and show my concern for the planet and what we're doing to it," she added.

M.Vacanti--INP