Marcus had argued that although he had been on an aircraft without permission he did have a reasonable excuse for doing so - the suspicion that the airport authorities and the British government were colluding in a war crime. Israel had been breaching international law by targeting its air strikes in Lebanon at areas and installations liable to contain civilians. They had asked the US for an emergency top-up supply of bombs. US planes delivering these armaments would need a fuel stop-over in the UK and Prestwick was one of the options.

Sheriff Montgomery said that Marcus had had no firm evidence to show that the UK government was aware that a war crime was being committed and so did not have a reasonable excuse for his actions.

Marcus told the Sheriff he would not pay the fine and asked that any substitute sanction be imposed immediately. He was sentenced to 28 days which he is likely to serve at HMP Kilmarnock*.

Marcus said: "I acted to protect my brothers and sisters in the Lebanon. It is the only way I know how to live."

A Trident Ploughshares spokesperson said: "It is disappointing that Sheriff Montgomery, who was up to that point meticulously fair in his approach, came up with such inadequate reasoning in reaching his verdict. The provision in the statute for justification by reasonable excuse cannot logically require absolute proof of the validity of that excuse. It rather allows for exceptional action by a person acting reasonably. As the Sheriff will know, there was at the time of the incident general and widespread public and governmental knowledge of both Israel’s indiscriminate bombardment and of the re-arming flights stopping over in the UK. In that context, given that no-one in officialdom had the will or gumption to act, Marcus behaved entirely reasonably. The Sheriff’s error is not trivial - it attacks the right and duty of ordinary citizens to take responsibility when humanitarian law is being breached. That is dangerous for us all."

"In the meantime there is continuing uncertainty about what, if anything, has been done by the authorities to ensure that Prestwick is not presently being used and will not be used in the future for the illegal transfer of armaments by the US military. In particular we are asking the Scottish Executive to take responsibility for this matter by ascertaining the current state of activity and commitments and acting appropriately on any knowledge gained. This is about war crime and the new Scottish Government needs to take a stand."

The activists carried out the inspections of Prestwick Airport on the night of the 6th/7th August last year.

*HMP Kilmarnock Bowhouse KILMARNOCK KA1 5AA 01563 548800