Britain’s most senior police officer has said he would “love” to be able to ignore protestors who bring traffic to a halt by locking themselves to motorway gantries.

Metropolitan Police Commissioner Sir Mark Rowley said he was deeply concerned about the impact on policing in London of having to deal with the disruption caused by the recent Just Stop Oil protests.

However, giving evidence to the Commons Home Affairs Committee, Sir Mark said the Highways Agency, now known as National Highways, had advised police that protestors who locked themselves on gantries over the M25 represented a safety hazard to motorists and should be removed before the road was reopened.

Asked why they could not just leave them there and allow the traffic to continue, Sir Mark said: “I am completely up for that.

“The Highways Agency feel there is a safety risk. They are concerned, I think, probably more about drivers being distracted than they are about the individuals.

“I would love to ignore all these characters but it is not always possible.”

Sir Mark confirmed that 12,000 officers had been involved in policing the Just Stop Oil protests in the course of October and November.

“It is deeply concerning to me that that 12,000 officer shifts that weren’t policing London’s communities because they were dealing with protestors in the centre of London or on the M25 or wherever,” he said.

Traffic on the M25 was brought to a halt on several occasions while other routes were also closed by protestors gluing themselves to the road.

Sir Mark said the law was currently unclear when it came to the action police could take to deal with disruptive protests.

“The balance between what is lawful and reasonable and what is not is very, very unclear,” he said.

“Parliament has left a very grey space about was is lawful and what is unreasonable disruption and are expecting police to work out a line in the middle of it.

“Things get blown around politically depending on who’s protesting, and what the issue is depends on who’s saying the police were too soft and who’s saying the police were too hard on the same incident. That’s the difficult context we are working in.”

He said the police had become much quicker in removing protestors but their legal advice was that they should not physically tear off protestors who glue their hands to road, which he said police in France do.

“Our advice is that we need to use solvent removers for the glue on the basis that reduces the harm done to (protesters). I’ll always go and reflect on it,” he said.

“The law is about using minimal force. If there is a way within a few minutes to remove somebody without causing significant harm to their hands then we are expected to do that.”