At least one protester was arrested on Wednesday after climate activists from Just Stop Oil climbed motorway signs on the M25, triggering major tailbacks.
Five demonstrators scaled gantries at three locations, causing police to close sections of the road.
The campaign group declared London’s orbital motorway a “site of civil resistance” following this week’s record temperatures and what they describe as the government’s “inadequate preparations” for climate change.
The group has issued a statement saying the record heatwave is “without doubt the most important moment in UK history”.
“All-time temperature records are being obliterated, thousands of people are expected to die from heatstroke and the liars and plotters who are vying to lead us are too busy fighting among themselves to even care,” the statement said.
Protesters climbed signs at junction 10 eastbound near Cobham, Surrey, the Poyle interchange at Heathrow between junctions 14 and 15, and in Dartford between the Queen Elizabeth Bridge northbound and junction 30.
Surrey Police later said a 22-year-old woman had been arrested on suspicion of causing a danger to road users, causing a public nuisance, and for being a pedestrian on the motorway.
"Three lanes needed to be closed while we worked to safely remove the woman, which involved a specialist team trained in dealing with incidents at height,” it said.
Louise Lancaster, 56, a former teacher and mother of three from Cambridge, was among those protesting.
In a statement on Just Stop Oil’s website she said: “The world is burning, it’s got to be obvious now to the people of this country, you have been lied to, fobbed off by the government and media fuelled by the oil barons and their greed. We have a serious, serious emergency; action needs to be taken. The government must not license 40 new oil fields. The government must take swift action to stand by its climate pledges and protect the future for our young people.”
Just Stop Oil has previously blocked the M25 and petrol forecourts, damaging more than 50 fuel pumps, with 35 people arrested during a protest in April.
The M25 has been the subject of repeated environmental protests after Insulate Britain also targeted the motorway last year.
The rise in incidents prompted the home secretary, Priti Patel, to push for new powers to curb such protests. “Serious disruption prevention orders” were among those included in a raft of controversial police powers in the new Public Order Bill, and would empower police to put electronic tags on disruptive demonstrators and restrict where they go, who they meet and what they do in person or online, even if they have not committed a crime.
However, Ms Patel’s own department – the Home Office – warned earlier this year that the plan would probably fall foul of the law.
A Home Office analysis suggested that persistent climate activists were “undeterred by the threat of arrest”, and said the proposals for serious disruption prevention orders “essentially take away a person’s right to protest and would very likely to lead to a legal challenge”.
