Insulate Britain once again descended on the M25, running into the main carriageway and bringing rush-hour traffic to a standstill.

Around 30 protesters tussled with police and blocked both carriageways near Junction 10 at Cobham in Surrey at 8am.

But police dragged activists to the hard shoulder and hurled their banners out of the way, arresting 23.

Within half an hour the road was open again.

The group said on its website new people had joined the protest along with some who have participated in all five.

Yesterday Boris Johnson said the group had achieved nothing but a spokesman said there was "no evidence" its cause had been set back.

Liam Norton said: “The idea that people would suddenly decide insulating our leaky homes is a bad idea as a result of our campaign is frankly laughable. We are simply asking the government to get on with the job.

“The people of Britain understand that climate change is a severe threat to everything they hold dear. They are looking to the government for leadership. We have a practical solution and have received encouragement for our aims from many construction industry professionals. ”

Dr Diana Warner, a retired GP from Gloucestershire, added: “Insulating homes is such a necessary action right now, for health, economy and climate. All our homes. Only the government can get that done. Boris just needs to get on with it. This is a practical way to start to level up Britain. No words, we need action and results.”

It was the fifth time the climate activists have obstructed the UK's busiest motorway.

Yesterday police swooped on protesters as they attempted to block the M25 in Kent.

Separate groups had already brought traffic to a standstill in Hertfordshire but at the Dartford Crossing junction 12 activists were detained before they could get on to the road.

A spokesman for Kent Police said: "At around 8.30am on Monday we received information that people were attempting to gain access to the M25 at junction 1a, the Dartford River Crossing.

"Officers attended and 12 people were arrested on suspicion of conspiracy to cause a public nuisance before they were able to gain access to the carriageway. They are currently in custody."

At 8am yesterday around 15 protesters turned up at Junction 18 in Hertfordshire and sat across a slip road, although within half an hour police had arrived and removed all the orange-bibbed campaigners.

Police were also called to the A1 M junction elsewhere in the county.

One protester told LBC: "Why has the government not responded? Reasonable protest is ignored, it is only by taking radical action we are going to get a response to a climate emergency."

Read more: What is Insulate Britain and what do they want?

Blue paint was poured across the carriageway and large hearts painted on the Tarmac this morning.

The group was responsible for huge delays in Kent and further afield last week.

In an announcement on its website over the weekend the group said only one person who participated in multiple roadblocks last week has been remanded in custody.

It said added it was "surprised" Highways England had refused to reduce speed limits to allow its members to protest safely.

In a statement the group said: "Earlier today Insulate Britian wrote to the Highways Agency and the relevant police forces, informing them of that the campaign would continue, and specified that supporters would be on the M25 network on Monday 20th September from 7am.

"Insulate Britain are asking the Highways Agency to review their previous decision not to reduce speed limits, even though they had been made aware that major disruption will be taking place.

"Given that this is a standard safety procedure when hazards occur on the motorway, Insulate Britain is surprised it has not formed part of the response to the campaign."

Last week they blocked the motorway at Dartford, with some protesters glueing their hands to the road.

Its members are demanding two policy changes from the government.

They want the government to immediately promise to fund and take responsibility for the insulation of all social housing in Britain by 2025.

They also want the government to "produce within four months a legally binding national plan to fully fund and take responsibility for the full low-energy and low-carbon whole-house retrofit, with no externalised costs, of all homes in Britain by 2030".

Outlining its request for Highways England to help facilitate the protest, the group said: "In the context of the horror of the climate crisis we believe that it is entirely proportionate to create disruption on the motorway network if it means the UK Government fulfils its legal obligation of staying below 2°C which will stop the unimaginable suffering for future generations."

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