Three Extinction Rebellion climate activists who disrupted commuters by gluing themselves to a train or climbing on its roof in a central London business hub have been told they will face no punishment over the protest.

Key points: The trio had argued that the protest was "necessary" to drive action on climate change

The trio had argued that the protest was "necessary" to drive action on climate change Extinction Rebellion launched in 2018 to highlight climate change risks

Extinction Rebellion launched in 2018 to highlight climate change risks The group has called for governments to reduce climate-changing emissions to net zero

Cathy Eastburn, 52, Mark Ovland, 36, and Luke Watson, 30, were convicted "with regret" by a jury but were handed conditional discharges, meaning they will face no further action as long as they commit no other offences for a year.

"I don't regret what I did at all," Eastburn said after the sentencing hearing.

"I'm not the sort of person who goes around climbing on top of trains and disrupting people. We did it for a very, very good reason — to sound the alarm."

Extinction Rebellion launched in London in 2018 using non-violent civil disobedience to highlight the risks posed by climate change, inspiring a wave of action globally with protests leading to thousands of arrests.

Eastburn, Ovland and Watson were charged with criminal disruption of the Docklands Light Railway train in Canary Wharf in East London on April 17, one of several protests targeting the city's financial districts.

The trio had argued that the protest was "necessary" to drive action on climate change during their trial at Inner London Crown Court this week.

They were found guilty after Judge Silas Reid ruled the activists could not use the "law of necessity" as a defence and the jury could not consider their intentions when reaching a verdict.

At the sentencing hearing, the trio was ordered to pay a total of 1,766 pounds ($3,333) in court costs.

An Extinction Rebellion spokeswoman said the trial was the first where arrested activists were heard by a jury.

'This is about life and death'

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 28 seconds 28 s Extinction Rebellion protesters were attacked by London commuters in October.

The protest group has called for governments to set a 2025 deadline to reduce climate-changing emissions to net zero, to declare climate emergencies and to set up citizen assemblies to give people a greater voice in political decision-making.

Police said more than 1,800 Extinction Rebellion activists were arrested during two weeks of street protests in October in London. Around 1,100 were arrested in similar protests in April.

Eastburn said she did not think mass arrests of the movement's protesters and trials over their disruptive actions would deter people from taking part in future protests.

"I don't think it should put anyone off — and I don't think it will," she said.

"This is about life and death and the future of our children, so people will do what they need to do."

The trial was the first where activists were heard by a jury. ( Supplied: Extinction Rebellion )

Reuters