Insulate Britain activist Stephen Pritchard has been sentenced to five weeks in prison for obstructing the M4 motorway near Heathrow airport in October 2021.
Pritchard and three others glued themselves to the tarmac on the motorway, causing traffic to be stopped in both directions for two hours and affecting thousands of drivers.
High Court injunctions were put in place after these road blockades last year.
Pritchard was convicted of causing a nuisance to the public by a jury at Inner London Crown Court.
Pritchard’s co-defendants, Ruth Cook, Roman Paluch-Machnik and Oliver Rock, were each given six-week sentences, suspended for 18 months and ordered to do 100 hours of community service.
Judge Silas Reid said Pritchard was being jailed due to his refusal to stop taking part in disruptive action as a matter of “conscience.”
The other defendants had previously said they had been deterred from future disruptive protest action.
The Judge stated: “The right to protest does not give you the right to disrupt the lives of thousands of people.”
Insulate Britain said this was the first time climate activists in the UK had been found guilty of the common law offence.
Speaking to the press after the sentencing, Cook, Rock, and Paluch-Machnik suggested that they would modify their protest tactics in response to accumulating court action against Insulate Britain and Just Stop Oil members.
Last month, Pritchard received a short jail sentence for defying a court order that prevented him and four others from protesting on the M25.