Police swooped on Insulate Britain protesters as they attempted to block the M25 in Kent.

Separate groups had already brought traffic to a standstill in Hertfordshire this morning 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 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."

It was the fourth time the climate campaigners had blocked the country's busiest motorway for the fourth time in a week.

The group, which was responsible for huge delays in Kent and further afield last week, said protesters would be on the road from 7am - but by 7.30am there was no sign of them.

At 8am 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.

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

Insulate Britain yesterday said 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."

The group caused fury when protests last week caused hours of delays for Kent commuters.

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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