Peace campaigning grandmother Sylvia Boyes, 57, was yesterday dramatically cleared of plotting to damage a Trident submarine while it was waiting to be tested in a dock.

Minutes after being found not guilty by a jury at Manchester Crown Court Sylvia, who moved to Keighley just before Christmas, said: "It is unbelievable.

"I am very happy both on a personal level and for the cause. I'll be coming home to Keighley to be with my family and not going to prison for what could have been a long time."

The jury had spent two days deliberating their verdict. Sylvia, who is married to Bradford based Unitarian Church Minister Robin Boyes, vowed to carry on her 'work'.

She says: " I will carry on organising meetings, writing letters and dealing with publicity as well as direct action. The main issue for us that there is still no ruling on the legality of Trident."

Sylvia and Open University tutor River, 45, formerly known as Keith Wright, went on trial after denying a charge of conspiring to commit criminal damage.

The trial heard that the pair - members of the disarmament group Trident Plough-shares - set out to damage the submarine Vengeance while it was being prepared to undergo sea trials at Barrow shipyard, Cumbria, in November, 1999.

The jury, of six men and six women, was told that the activists were caught equipped with hammers and an axe before they had a chance to swim to the submarine.

Elizabeth Nicholls, prosecuting, told the jury: "I am sure that whatever the outcome of this trial you will conclude your jury service with a feeling of utter respect and admiration for the strength and integrity of these two defendants' beliefs."

Miss Nicholls said the defendants were both members of a group called Trident Ploughshares which wanted to bring about the end of all nuclear weapons.

The court heard that the defendants were found on November 23. Sylvia was found first, wearing a hooded wet suit, with a hammer and screwdriver attached to her belt bearing anti-nuclear slogans.

Sylvia who has been imprisoned 'seven or eight times' before adds: "We did not deny doing it. Our defence is one of lawful excuse in that we committed a crime in order to prevent a bigger one being carried out - nuclear war."

Durham born Sylvia, has been involved in the peace movement for most of her life - starting off by running stalls and fund raising. She became involved in direct action after going to Greenham Common in 1982. "I brought up four children and as they grew older I became more and more involved. It is my time and I see it as my work."

Her husband Robin says: "At times it's rather like being married to Joan of Arc. She's got a vocation that she's got to follow and I, as a minister, who preaches tolerance, I've got to be tolerant and let her get on with her vocation."

Sylvia's arrest was filmed by a BBC crew who were making a documentary on her exploits. It can be seen on BBC1 next Monday night.