Forty-nine members of Insulate Britain have been arrested after the climate activist group blocked three major junctions in defiance of a series of injunctions banning them from protesting anywhere on England’s strategic road network.

In their 15th day of action since starting their campaign in mid-September, members of the group staged roadblock protests near the M25 Dartford crossing in Kent and another on the A40 in West London.

According to the group’s estimates, 146 members have been arrested 690 times since 13 September. It is calling on the government to commit to insulating all Britain’s homes by 2030 as a first step to tackling the climate crisis.

In Kent, police arrived within minutes of 14 protesters walking out on to Crossways Boulevard in Dartford. The protesters were quickly intercepted and arrested, many before they could glue themselves to the road surface, and traffic was flowing again by 8.30am.

However, that action was a decoy for another nearby on junction 1a of the M25, where about an hour later another 14 protesters walked into traffic and glued themselves down. It took officers nearly two hours to get traffic flowing again at that location.

At the same time in Acton, west London, a number of protesters walked out on to the junction of the A40 and the A4000. Before police were able to reach the scene two older protesters were sprayed with blue ink, while passersby snatched their banners.

Sitting by the side of a motorway slip road in Dartford after being arrested for the ninth time as part of the campaign, Rev Sue Parfitt, 79, from Bristol, said: “We have to do this. It’s four days until Cop [26, the climate summit in Glasgow] starts. If they don’t do better than the previous 25 Cops, we’ve had it.

“If we slow down the [climate] emergency, it’s worth doing this; and we are going to go on doing it until our last breath, because what else can we do?”

Benjamin Buse, 36, from Somerset, who was lying on the floor nearby after being arrested, said: “We are here because of the need for insulation, and because everything else has failed. We know disruption causes political pressure, which gets media attention and government attention. People have been campaigning on these issues for decades, and we have waited too long.”

The Metropolitan police said 17 activists had been arrested in Acton, where traffic had been diverted to avoid the roadblock. “Police worked quickly to get roads open again,” the Met said. “Traffic is now flowing.”

Kent police said a total of 32 people had been arrested in Dartford, including 14 at each roadblock and a further four in a nearby car park. All those detained were arrested on suspicion of obstructing a highway or conspiring to cause a public nuisance and remained in custody, the force said.