Environmental activists blocking the M25 face possible imprisonment after National Highways was granted an injunction against the protests, Transport Secretary Grant Shapps said.

Campaign group Insulate Britain has shut down parts of the M25 five times in just over a week.

It has been reported that many of those taking part in the demonstrations have been arrested and released several times.

The Department for Transport said the injunction means the punishment for taking part in the protests will be tougher as activists will be in contempt of court and could be detained.

Mr Shapps wrote on Twitter: “Invading a motorway is reckless and puts lives at risk.

“I asked National Highways to seek an injunction against M25 protestors which a judge granted last night.

“Effective later today, activists will face contempt of court with possible imprisonment if they flout.”

Home Secretary Priti Patel said the “important injunction” means “people can get moving again” on the M25.

“We will not tolerate lives being put at risk,” she said.

“Those who continue to do so risk imprisonment.”

Surrey Police arrested 38 activists from the group on Tuesday who had targeted junctions nine and 10 of Britain’s busiest motorway.

Footage taken at the scene by LBC showed the protesters walking on to the motorway and sitting down on the ground in front of moving traffic.

Some then held up banners reading “Insulate Britain” and poured blue paint on to the road, before they were dragged away by officers.

Insulate Britain confirmed it led the demonstration on Tuesday, adding that new people have joined its campaign to improve home insulation in addition to others who have been involved in similar demonstrations in Hertfordshire, Kent, Essex and Surrey over the past two weeks.

It added that the recent rise in gas and electricity costs has “increased the urgency” for change, and it will end its campaign as soon as it hears a “meaningful commitment” to its demands.

Insulate Britain spokeswoman Zoe Cohen was asked on BBC Radio 4’s Today programme if the injunction will stop the protests from taking place.

She replied: “The people taking part in these actions understand that the risks they are taking are because that we have tried everything else to make the Government protect us from the predicted impacts of climate chaos.

“That involves the loss of all that we cherish, our society, our way of life and law and order.

“We’re calling for the installation and whole house retrofitting of social housing by 2025 and all homes by 2030, because this is the most effective way to reduce emissions, save lives from fuel poverty.”

Assistant Chief Constable Chris Noble, the National Police Chiefs’ Council lead for policing protests, told the programme: “Police aren’t anti-protest but we are pro-responsibility.

“This is not a benign supermarket car park that this is taking place on.

“Probably the people most likely to come to harm at the moment is probably initially police officers who are having to run across motorways to try and remove protesters as well as ironically keep them safe from themselves.”