Six environmental protesters were convicted after they were denied the ability to put a “reasonable excuse” defence or climate facts before the jury, despite these being afforded to other activists acquitted for taking part in the same demonstration.

After an eight-day trial at Southwark crown court in London, the six Just Stop Oil (JSO) activists were found guilty of public nuisance, which carries a maximum 10-year sentence, for climbing gantries on the M25 in 2022 to demand an end to new fossil fuel projects. They will be sentenced next month.

The way their case was handled contrasts starkly with that of three other JSO activists who took part in the same demonstration on London’s orbital motorway.

They were found not guilty of public nuisance after the judge at Guildford crown court allowed them to argue a defence of reasonable excuse and prosecutors permitted them to include 12 climate facts in the agreed facts – undisputed by both prosecutors and defence lawyers – presented to the jury. The verdicts in the two cases were less than three weeks apart.

Adelheid Russenberger, a history PhD student from London, who is one of those being sentenced at Southwark crown court next month, said: “It was just a complete disparity in how the judges treated the case and, to an extent, how the prosecutors dealt with them.