Twelve people have been arrested over a drone protest at Heathrow that activists say will continue over the weekend.

Protesters from a group called Heathrow Pause failed to cause disruption at the airport, but say the action highlights the devastating role air travel plays in the escalating climate emergency.

The first volunteer attempted to fly a drone within the airport’s three-mile (5km) exclusion zone at 3am on Friday in a bid to disrupt flights, but protesters said the authorities used jamming technology to prevent it taking off.

A spokesperson for the airport said: “Heathrow’s runways and taxiways remain open and fully operational despite attempts to disrupt the airport through the illegal use of drones in a protest nearby.

“We will continue to work with the authorities to carry out dynamic risk assessment programmes and keep our passengers flying safely on their journeys today.”

The Metropolitan police confirmed that 12 people had been arrested, seven pre-emptively on Thursday and another five on Friday once the demonstration had started. A statement added that all the arrests were on suspicion of conspiracy to commit a public nuisance and that there had been no breach of airport security.

Despite its failure to disrupt flights, a spokesperson for Heathrow Pause said the action had triggered “a sensible, honest conversation throughout society on the dangerous folly of Heathrow expansion, with the ultimate objective of cancelling the third runway”.

Activists said at least one drone had been flown successfully, and that they planned to continue attempting to fly drones at head height within the airport exclusion zone over the weekend.

One of those arrested on Friday morning, James Brown, said he had been left with no other choice but to protest. Speaking before his arrest, he said: “Even though parliament has formally recognised the climate emergency we are facing, our own government is still pursuing plans to build a third runway at Heathrow,” he said.

“This hypocrisy, and the general negligence of the aviation industry to face up to its contribution to the climate emergency, has forced me into considering arrest and, if necessary, imprisonment, to wake people up to the dire situation we are in.”

Police made seven pre-emptive arrests of activists including Roger Hallam, a co-founder of Extinction Rebellion.

The protests mark the start of what is likely to be an upturn in environmental activism over the coming weeks. Extinction Rebellion protesters held a die-in at the start of London fashion week on Friday, and millions of people around the world are expected to take part in the climate school strikes next Friday. Extinction Rebellion are also planning weeks of mass civil disobedience in London in October.

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It will also be a crucial time for world leaders with key environmental gatherings planned in New York and Chile before the end of the year.

At Heathrow, protesters had planned to fly drones away from flight paths at no higher than about 1.8 metres (6ft). They notified the airport and the authorities of their plans weeks ago and said that once a drone flight was over its pilot would phone the police and wait to be arrested.

They had believed this would force the authorities to shut down Heathrow’s operations, but a spokesperson for the airport said this assumption was wrong because an ongoing “dynamic risk assessment” would look at each incident on a case-by-case basis.

Before he was arrested, Hallam said the proposed third runway expansion would “provide another few years of business as usual, until everything collapses”.

“We are in a ‘time of consequences’, as Churchill called it in response to the Nazi threat in 1936. The consequence of not rebelling is indescribable suffering and death for billions of people,” he said. “The consequence of rebellion is a chance to avoid the worst. Rebellion means mass economic disruption and deep personal sacrifice. I am a rebel.”