The group has support from the Bath-based Whale and Dolphin Conservation Society (WDCS) and, to a lesser extent, the RSPB. Both groups believe the development of the frontier to the west of Shetland could damage cetaceans and birdlife.

Greenpeace claims the world cannot afford to burn more than a quarter of known fossil fuel reserves if climate changes and sea-level rises are to be avoided.

Therefore, the group believes there is little point in further oil exploration, particularly in the Atlantic fields off Shetland.

At a press conference onboard the group's campaign vessel of the same name, which was berthed at the OIL base earlier this week, Greenpeace's oil tearn campaigner Robbie Kelman said the issue of fossil fuels had to be put firmly on the political agenda.

"The Atlantic frontier range is of particular concern-we have seen the pollution and oil wells out in the North Sea and that is going to be replicated out in the Atlantic," Mr Kelman said.

Together with climate campaigner Matthew Spencer and wildlife campaigner Liz Pratt, the trio helped to launch Greenpeace's latest report-Putting the Lid on Fossil Fuels-which calls for the Atlantic to be made a frontier against oil exploration.

The report claims the oil industry is out-dated and exploration of the Atlantic Frontier was conceived well before the world was aware of the problem of climate change.

The Earth's temperature has gradually been rising, an effect accelerated by the burning of fossil fuels. Greenpeace claims that while the Government says it is aware of the impact of fossil fuels, massive searches for new oil and gas fields continue.

As well as calling for more research into alternative energy sources such as solar power, the 65-page report, also highlights the importance of the Atlantic for whales and dolphins as well as deep-water fish and birds.

On this issue, Greenpeace has received support from whale experts throughout the world through the WDCS.

In a joint statement warning of the consequences of continued oil exploration, the experts said:
"From our knowledge of the biology of marine mammals, these animals are likely to be sensitive to noise, disturbance and other pollution associated with offshore oil and gas development."

The society said the seas to the north and west of Scotland, and in particular Shetland, were home to some 21 different species of cetaceans and seismic testing was known to adversely affect whales.

Mr Kelman said there was no reason why an ocean area should not be classed as a wildemess area and protected by law on environmental grounds.

On Wednesday the group held an open afternoon onboard their vessel, before leaving Lerwick for the oil fields west of Shetland. Campaigners said they planned to stay in the area for the "forseeable future".