SIX Greenpeace activists yesterday boarded an oil exploration vessel in Ullapool harbour and chained themselves to it in a bid to prevent it starting seismic testing in the North-east Atlantic.

The campaigners boarded the 91-metre Atlantic Explorer at 4.50pm. She is due to begin tests for Conoco in tranche 52 of the Atlantic Frontier.

Two attached themselves to the bow line in harnesses, 13 metres above the water, while two others climbed up the crane with a large banner reading "No New Oil. Greenpeace".

Another activist, a woman, secured herself on to the helideck, while another protester was attached to the stern line of the rear of the boat.

The protesters were asked to leave but they refused to do so and the boat operators, PSG, called in the police.

Sgt Paul Eddington, of Ullapool Police, said: "We are not planning to take any action as it is entirely peaceful.

"No attempt is to be made to remove any of the activists at the moment, we will jut wait and see what happens."

But it was thought last night that the campaigners were staying put.

Speaking from Ullapool, Greenpeace campaign director Chris Rose said: "There is only one ultimate result of seismic testing and it is environmental damage-to our climate, to our ocean and to our marine wildlife."

Yesterday's action is the second time Greenpeace has taken non-violent direct action to stop seismic testing in the North-east Atlantic.

The environmental group has lodged papers in the High Court in London, seaking leave for a judicial review of the Government's alleged failure to consider the habitats directive in relation to coral reefs in the area.

Caroline Churchill, of Conoco, said: "Stunts such as this are not only potentially dangerous but are clearly not aimed at civilised debate."

She stressed that Conoco was licensed by the Government.