BBC Legal Affairs Correspondent Joshua Rozenberg: "A famous victory"

The Law Lords, in a 3-2 vote, ruled that two demonstrators were wrongly convicted of trespassory assembly under the 1986 Public Order Act.

Those who ruled in favour of the right to demonstrate peacefully included the Lord Chancellor, Lord Irvine of Lairg, who said the case raised "an issue of fundamental constitutional importance".

The offence of trespassory assembly was added to the Public Order Act in 1994 by the then Home Secretary Michael Howard.

Access rights

Dr Jones: "This is a very important victory and we're absolutely bloody delighted"

The first two people to be charged with the offence were university lecturer Dr Margaret Jones and student Richard Lloyd.

They had taken part in a peaceful roadside demonstration in June 1995, marking the 10th anniversary of the infamous "Battle of the Beanfield", when demonstrators sought to gain access to the ancient stones.

Salisbury District Council had made an order prohibiting the holding of all anniversary "trespassory assemblies" of 20 or more people within a radius of four miles from the junction of the A303 and the A344 adjoining the ancient monument.

English Heritage have sought to protect the fabric of Stonehenge

Dr Jones and Mr Lloyd were arrested when they refused to move on.

They were convicted by Salisbury magistrates, but cleared on appeal by a judge Salisbury Crown Court.

He ruled that any assembly on the highway was lawful as long as it was peaceful and non-obstructive.

In January 1997 two High Court judges ruled that the Crown Court had misinterpreted the law.

'Just count up to 20'

Lord Justice McCowan, sitting with Mr Justice Collins, said in order to obtain a conviction, the prosecution need prove no more than that the assembly consisted of 20 or more persons who knew it was prohibited.

But on Thursday Lord Irvine and two other Law Lords ruled there was a "public right of peaceful assembly on the highway" and granted the pair's appeal.

Lord Irvine said there could be no basis for distinguishing highways on publicly-owned land from those on privately-owned land.

But he said any fears the rights of private landowners might be prejudiced were "unfounded".

'Private landowners still protected'

Lord Irvine said: "The law of trespass will continue to protect private landowners against unreasonably large, unreasonably prolonged or unreasonably obstructive assemblies upon these highways."

He said if the High Court's interpretation of the law had been right it would have meant any peaceful assembly, no matter how minor or harmless, would be unlawful.

That would have clashed with Article 11 of the European Convention on Human Rights which confers a "right to freedom of peaceful assembly".

A spokesman for English Heritage, which looks after Stonehenge, said they would be obtaining a copy of the judgement and considering its implications.

Afterwards, Dr Jones said: "We started out to protest the Criminal Justice and Public Order Act. We have ended up with the first assertion in British law of a positive right to peaceful assembly.

"It's far, far better than we could have hoped for."

Co-defendant Mr Lloyd said: "I just wish we hadn't had to go through a four-year legal battle to stand peaceably by a road."

Liberty, the human rights group which backed the case, hailed the decision as "historic".

Philip Leach, Liberty's director of law and policy, said: "This decision establishes for the first time in this country the positive right of peaceful protest on our streets.