Counsel for about 60 of the 120 passengers who were prevented from attending the vigil at RAF Fairford in March said that the action taken by Gloucestershire Police was unlawful.

Michael Fordham said: “We submit both by reference to well established common law and also by reference to human rights law, as it now is in domestic law from October 2000, that that police action was an abuse of power.

“We submit that the the police stepped well outside the legal parameters on their powers and that the action taken was unjustified.”

He told Lord Justice May and Mr Justice Harrison, sitting in London, that the three coaches from London were intercepted in a lay-by in Lechlade at 12.50pm, searched and items were seized.

At 2.15pm, the decision was taken to return the coaches to London non-stop under police escort because of the view taken about preventing violence by hard-core demonstrators.

Mr Fordham said that both the action of turning away and of forcible return were unlawful.

“This was a case of a preventative restraint, not because of anything that had happened but because of something that was said to be anticipated.”

He said that he did not accept that there would have been a breach of the peace on arrival at Fairford.

Nor did he accept that there were no steps which the police could have taken to consider the different passengers and to seek to differentiate between them.

He said that the operation at Fairford, which was used by American B-52 bombers, was the largest and most complex police operation ever undertaken by Gloucestershire Police.

“The day was very important to them and very important to those who wished to go to Fairford to exercise their rights of assembly and expression.”

The protesters were utterly opposed to the US-led military assault on Iraq and wished to exercise their deeply-held beliefs through peaceful protest.

Mr Fordham said that the police regarded their operation as a great success in achieving their strategic objectives of preventing violence and facilitating peaceful protest.

Gloucestershire Police, which are contesting the judicial review proceedings, argue that their officers were not only entitled to take the action they did – they were obliged to.

The case is expected to go into tomorrow with no immediate decision.