Five climate campaigners have been arrested on suspicion of planning to fly drones near Heathrow Airport.

A group called Heathrow Pause, an offshoot of Extinction Rebellion, had planned to disrupt flights to highlight “the grave risk of airport expansion during the climate and ecological emergency”.

Activists said the devices would be flown on Friday at head height and away from flight paths to avoid any safety risk.

But London’s Metropolitan Police said the action would be criminal and anyone taking part would be arrested.

Heathrow Pause said those arrested “preemptively” included prospective drone pilots Roger Hallam and Mike Lynch-White.

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The five, three men and two women, were taken to a London police station and were still being held on Thursday evening, officers said.

The climate group had announced it intended to fly the machines in the 3.1-mile exclusion zone around the airport, potentially disrupting hundreds of flights.

Members said its activists were “prepared to pay a very high price” to protest against the planned third runway.

They are also calling for the government to “tell the truth” about the climate crisis and act on parliament’s declaration of a climate emergency.

In a video of one of the arrests, outside an east London cafe, three plain-clothes officers handcuff Mr Hallam and caution him.

Someone off-camera asks what he’s being arrested for and he says: “Flying a drone – I haven’t done it yet – on conspiracy”.

Replying to another – incomprehensible – question, Mr Hallam, 53, an organic farmer and co-founder of Extinction Rebellion, says: “Whatever it takes,” before being put in a car.

Heathrow Pause said those flying drones were committed to “non-violence, transparency and accountability and to cooperating with the police as far as is possible”.

But police had urged anyone intending to fly drones illegally near Heathrow to abandon their plan.

Deputy Assistant Commissioner Laurence Taylor said: “We have carried out these arrests today in response to proposed plans for illegal drone use near Heathrow Airport which protest group Heathrow Pause have said will take place tomorrow morning.

“Our policing plan is aimed at preventing criminal activity which poses a significant safety and security risk to the airport, and the thousands of passengers that will be using it.”

He said the arrests were a proportionate response to preventing criminal activity that could significantly affect a major piece of national infrastructure.

“We remain fully prepared for the planned protest tomorrow, and will work quickly to identify criminal activity and arrest anyone committing offences,” Mr Taylor added.

Mr Hallam said earlier this week: “The Heathrow expansion is the biggest carbon-intensive infrastructure project in Europe, so I’ll be flying a drone at head height, some distance from Heathrow. It’ll be 100 per cent safe and 100 per cent illegal. So I’m likely to get arrested and I could be going to prison.”

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He said he was doing it for the future of the world’s children.

“And I’m also doing it because I’m a farmer. And as a farmer I’ve experienced the stress and horror of losing all my crops because of climate extremities.”