The 14 Greenpeace protesters are charged with aggravated trespass and criminal damage at Marchwood Ports on 3 February last year.

They group had said the protests were "necessary" to stop an "illegal" war.

But a judge ruled that Lord Goldsmith's advice on the legality of Iraq war was not admissible evidence.

Loss of life

Greenpeace lawyer Tim Owen QC, had applied to summon Lord Goldsmith to court under Section 97 of the Magistrates Court Act.

But District Judge John Woollard said he would not issue a summons at Southampton magistrates court heard on Wednesday.

He said: "I do not consider that the Attorney General's advice as to the legality of the war in Iraq can properly be admitted in deciding whether or not the defendants reasonably believed that their actions were inevitable."

Lord Goldsmith's QC, David Perry, told the court: "It has never been the case in criminal law that evidence is admissible to inform the court as to what is reasonable."

He also told the court that the Attorney General's evidence amounted to a "matter of opinion".

Whistleblower's defence

The group had argued the actions they took in Southampton were "necessary" to prevent the loss of life and the crime of an "illegal" war.

Mr Owen had claimed Lord Goldsmith's advice to ministers was "crucial" to the activists "defence of necessity", which was used by GCHQ whistleblower Katherine Gun.

The case against Mrs Gun was dropped after her lawyers asked to see Lord Goldsmith's advice last month.

The defendants are Belinda Fletcher, 26, from Oxford, Oliver Knowles, 28, of Willesden Green, north London, Ben Ayliffe, 26, from Highbury in north London, Laura Yates, 26, from north London, Jim Footner, 26, from Shropshire, Robin Oakley, 29, of Fleetwood, Lancashire.

Also facing charges are Graham Thompson, 30, of Romford, Essex, Natalie Duck, 27, from north London, Helen Wallace, 39, of Buxton, Derbyshire, Ashby Smith, 25, from Colorado, USA, Jens Loewe, 35, from Hamburg, Germany.

Richard Watson, 38, from Burnley, Lancashire, Rachel Murray, 30, from Glasgow and Janice Harron, 38, of Donegal, north west Ireland are also charged.