Five protestors who took to the track at Silverstone at the start of last year's British Grand Prix have been found guilty of causing a public nuisance and face possible jail time, together with a sixth protestor.
Mr Justice Garnham delivered the verdict on Friday at Northampton Crown Court on four men and two women who were part of a Just Stop Oil demonstration at the event on Sunday, July 3.
Prosecutors said the group had caused an immediate risk of serious harm by their actions, which saw five of them scale the barriers at Silverstone's Wellington Straight and take to the track as two F1 cars passed close by.
Footage was shown of F1 drivers Yuki Tsunoda and Esteban Ocon passing the group who were sitting on - or being dragged off - the track at the time.
The race had already been red-flagged at this point due to a serious accident involving Alfa Romeo's Zhou Guanyu, who had been flipped upside down and sent into the gravel at the first corner.
This unforeseen event meant that the cars were no longer up to full speed by the time they reached the site of the on-track demonstration, which helped ensure no one was actually hurt.
"The prosecution say that there was clearly an immediate risk of serious harm being caused," said Simon Jones, counsel for the prosecution. "Plainly they could have been struck by fast-moving vehicles with obvious severe consequences.
"We say that that their actions also caused risk to the drivers themselves and the marshals," he added.
The protesters argued that the demonstration had a "meticulous" safety plan and did not pose a risk of serious harm to themselves, or to the drivers or safety workers at the track.
Alasdair Gibson, Louis McKechnie, Bethany Mogie, Emily Brocklebank and Joshua Smith were convicted of accessing the track. A sixth man, David Baldwin, was arrested in a nearby car park in possession of glue, cable ties and a Just Stop Oil banner.
McKechnie told jurors the group had planned the protest over two and a half months to make it as safe as possible.
Northamptonshire said at the time that it had been alerted to possible protests at the British GP and had been on high alert.
"I'm really disappointed that this group of people ignored our warnings prior to race day and made the incredibly dangerous decision to enter the track," said event commander and chief inspector Tom Thompson.
"We offered to facilitate a peaceful event at the circuit but they instead chose to put the lives of the drivers, marshals and volunteers at risk," he added. "It's incredibly disappointing that anyone would make the decision to do this."
"Everyone has the right to speak out on issues, but no one has the right to put lives in danger," said F1 CEO Stefano Domenicali. "The actions of a small group of people today were completely irresponsible and dangerous."
Lewis Hamilton had caused a stir by saying "I love that people are fighting for the planet and we need more people like them," but Mercedes issued a press release clarifying that he supported the right to protest, not the track invasion.
After handing down the verdict, Mr Justice Garnham said: "All of them [the protestors] should understand and be in no doubt that I will be considering all possible options when it comes to sentence, and that includes the possibility of a prison sentence."
All six were granted bail after providing a verbal commitment not to become involved in further protests while awaiting sentence. They will return to court to be sentenced on March 31.