ENVIRONMENTAL protesters yesterday admitted sabotaging a buoy being used in the hunt for new oil reserves in the Atlantic.

Greenpeace members took to the sea in inflatable dinghies to remove the buoy's satellite antenna as part of an ongoin campaign that has also seen protesters spending more than a month on inhospitable Rockall.

The buoy is a vital part of seismic tests being carried out by the research vessel Pacific Horizon on behalf of a group of oil companies, headed by Texaco, hunting new reserves west of Shetland.

The ship trails three-milelong "streamers" fitted with seismic guns that fire shocks into the sea. Echoes of the shocks are picked up by microphones to reveal information about the geological make-up of the seabed.

Without the buoy, there is no way to keep the streamers in place, or to transmit the information that is picked up.

For four weeks, the ship MV Greenpeace has dogged the Pacific Horizon in an attempt to disrupt its work.

Over the past few days, swimmers have been lowered into the chilly Atlantic ahead of the ship, forcing it to change direction and invalidating its tests, which depend on keeping a straight course.

A Greenpeace spokeswoman explained: "This campaign is all about climate change. The world knows that it cannot afford to burn even a quarter of existing fossil fuel reserves without causing climate change, so what is the point of looking for more?

"Someone, somewhere, has got to have the sense to stop looking for new reserves and start phasing out fossil fuels."

Yesterday's incident, which took place about 190 miles from Rockall, led to the Paciflc Horizon giving up its tests for the day, she said.

A Texaco spokesman said: "Texaco confirms that illegal action by the master and crew of the MV Greenpeace has resulted in a temporary cessation of the seismic survey on Tranche 36, approximately 60 miles north-west of Lewis . . .

"It is umderstood that members of the Greenpeace crew boarded the tail buoy, which was under tow at the end of the seismic string, removed radar and satellite navigation equipment and attempted to overturn the buoy. The equipment was taken to the MV Greenpeace."

Texaco and its seismic contractor, Horizon, would continue to take every step to ensure that no personnel were exposed to risk. "Both companies urge Greenpeace to cease taking action which presents a high level of risk to the safety of their own and the companies' personnel offshore."