Just three of Insulate Britain's motorway blockades have cost taxpayers nearly ￡1 million, a court has been told.
Documents from lawyers for National Highways said that three days of protests on the M25 and A20 last month were “incredibly dangerous” and “unpredictable”.
Saira Kabir Sheikh QC argued: "The estimated, lower bound, costs of these protests on drivers are substantial, with the lowest still causing ￡20,124 in loss and the most impactful, so far, costing an estimated ￡324,107.
"This does not account for any costs associated with missed appointments, disruption to manufacturing or retail, missed transportation slots at airports or ports, or the direct cost to police or National Highways of managing the incidents."
She added that Duncan Smith, the acting executive director of operations of National Highways, warned that it is "only a matter of time" before a "serious incident", such as a fatal injury, happens because of the protests.
Nationwide injunction extended
It came as Insulate Britain members appeared before a hearing at the Royal Courts of Justice on Thursday morning, with a judge extending a nationwide injunction banning their presence on any UK motorway or A-road.
Cathy Eastburn said at the hearing that despite breaking the injunction herself “I haven’t even read the injunction because it’s, like, really long”.
The injunction, published by National Highways on its website, is six pages long.
Mr Justice Lavender adjourned the decision on whether to grant a continuation of the injunction until November 11, during which time it would remain in force.
During the hearing, Insulate Britain activists argued that they needed more time to get some legal representation, as well as bring the injunction to the attention of campaign groups like Extinction Rebellion, which believes in the legal right to protest.
They argued that the injunction was incompatible with a recent Supreme Court ruling called the “Ziegler Judgment”, a legal loophole which they claimed enshrined their legal right to protests on roads.
The ruling has been cited by Insulate Britain and Extinction Rebellion as justification for the legality of their blockades. It is understood police forces have been taking it into consideration while arresting protesters over the last two months.
The Telegraph understands that Extinction Rebellion is undergoing discussions on whether to join forces with Insulate Britain to oppose the injunction next month, despite previously disowning the group as being an entirely separate entity.
Dr Diana Warner, a member of the group, told the court: "We are talking about an existential emergency, not about people being late to their jobs or losing a bit of money. We need to change what we're doing for everybody's future.
"This is an example of bullying. No other groups are being singled out for doing worse. It's bullying and I hope this court doesn't sanction it."
Despite there being 122 named people on the injunction, the order approved by the High Court on Monday evening could apply to anyone found to be “blocking, slowing down, obstructing, or otherwise interfering with the flow of traffic”.
The judge also approved an application by National Highways to allow police forces to share the names and addresses of those they have arrested during the two months of protests, so that the Government agency can take them to court for contempt.
Currently, nine protesters have a date set for the Royal Courts of Justice for contempt of court on November 16. They could get up to two years in prison if the judge rules that they broke any of the High Court injunctions imposed on them.
A spokesman for Extinction Rebellion said before the judgement on Thursday: “The injunction, which prohibits people from Insulate Britain, and anyone else, from protesting on any part of the strategic road network in England is breathtaking in its scope and a massive overreach.
“It appears to contradict the Ziegler ruling, which determined that obstruction of the highway as a form of protest was lawful in certain circumstances.”