Most of the world's major oil companies are now scouring the Atlantic Frontier, and the British company BP is due to start producing oil from the first field in the area, Foinaven, later this year. The Department of Trade and Industry estimates that the whole region contains up to 1240 million tonnes of oil.

However, parts of the Atlantic Frontier also contain an unusual cold-water coral, Lophdia perxsa, which scientists believe could harbour as many fish and other species as tropical corals. "L. pertusa is a macro-organism of wonderful diversity and splendour," says Graham Shimmield, director of the Scottish Association for Marine Science (SAMS), based in Dunstaffnage, near Oban.

SAMS is participating in a £1.8 million study of the environmental impact of oil development in the Atlantic Frontier, funded by the government and the oil industry. The study, which has only just started, includes the first attempt to map the presence of L perassa and assess how it might be affected by oil exploitation.

Forging ahead with oil development at the same time as studying its impact on the coral "seems to be rather hasty", says Shimmield. "In the ideal world we would collect the data, which should take about two years, before we took the next step."

Shimmield's colleague at SAMS, John Gage, thinks that L pertusa could be vulnerable to chemical contamination from oil wells. The coral is associated with at least 300 species of fish, crustaceans and anemones, he says. It grows at a maximum of two centimetres a year, and large reefs off Norway are probably several thousand years old. Alex Rogers of the Plymouth Marine Laboratory warns that L peratsa could be smothered and killed by clouds of sediment kicked up by drilling.

However otber scientists, such as Keith Hiscock of the government's Joint Nature Conservation Committee, argue that oil exploitation is unlikely to do as much damage as deep-sea fishing boats, which catch lumps of coral in their nets when they trawl wide areas of the seabed.

The enviromnental group Greenpeace is accusing the British government of breaking European law by failing to protect the coral, and is threatening legal action.

BP says that steps will be taken to protect any L pertusa found in oil fields. "We have a strong track record on the environment," says a spokesman for the company, "and we obviously intend to maintain it."