They have been charged with obstructing police, unauthorised boarding of a vessel and and dangerous navigation.

Two Spanish journalists were also due to appear charged with resisting police and threatening behaviour.

The protest in the British possession of Gibraltar was against the use of single-hull oil tankers, which Greenpeace says represent a special environmental hazard.

The action followed the sinking of the single-hull tanker Prestige, which foundered last November off Spain's northwestern coast, causing Spain's worst ecological disaster of this kind when thousands of tonnes of oil spilled from its hold.

The accused boarded the vessel Vemamagna in Gibraltar harbour last January

A Spaniard and a Portuguese are also among the Greenpeace activists on trial.

Twenty poeple including 12 journalists were arrested during the protest demonstration.

TERRA.WIRE