The group of 13 climate change protesters who blocked the runway of Heathrow Airport have been found guilty of aggravated trespass and entering a security restricted area.
The judge said the defendants were all "principled people" and Heathrow is in breach of EU emission regulations, but she did not accept that their actions were necessary to prevent death or serious injury.
Senior Correspondent Simon Harris reports.
Members of the Plane Stupid campaign group cut a hole in a fence and made their way on to the north runway atHeathrow in the early hours of July 13 last year.
Their actions caused disruption for thousands of passengers, with 25 flights cancelled.
The 13 protesters, from climate change protest group 'Plane Stupid', were told to expect an "immediate custodial sentence."
The protesters had enjoyed a high level of political support, with Green Party leader Natalie Bennett and shadow chancellor John McDonnell due to be called as defence witnesses, but were barred from doing so by the judge.
Judge Wright, who said the cost of the disruption was "absolutely astronomical", added there had been times during the week-long trial at Willesden Magistrates' Court when defendants seemed "at pains to make political points".
Supporters clapped and cheered ad the protesters left court, but several of those convicted they were "terrified".
A Heathrow spokesman said:
Superintendent Andy Jones, from the Met's Aviation Policing team, said the convictions "send out a clear message that such behaviour will not be tolerated", and appealed to protesters to demonstrate peacefully and legally.