GREENPEACE has come under fire from an independent environmental consultant for its campaign against exploration and development on the Atlantic frontier.

Prof Cliff Johnston told a conference organised by the pressure group in London this week that production from the Atlantic frontier was insignificant in world terms.

"If somebody wants to stop oil and gas production they should be chaining themselves to railings in Saudi Arabia," he said.

Prof Johnston said the UK was responsible for only 4% of world production and 0.4% of global reserves of oil.

He said Greenpeace should be focusing on larger consumers of energy, specifically the US, which used 2.069bn tonnes of oil equivalent to fulfil is energy requirements in 1995.

The conference, entitled Denizens of the Deep and concerning the marine life of the Atlantic Margin, was attended by environmentalists, scientists and representatives from major oil and gas companies.

In response to the criticisms Lord Melchett, Greenpeace UK's executive director, said: "We are miniscule by oil industry standards . . . if you are small you have to pick global priorities with care."

Lord Melchett said it was time for a line to be drawn in the sand and the Atlantic Margin was where that line would be drawn.

But Prof Johnston attacked an "insanity ladder" which resulted in the multiplication of a few facts leading to the conclusion that Atlantic margin development should be stopped.

Earlier delegates heard presentations on the diversity of life in the area. There was lively debate over the extent of Lophelia corals in the area and how they could be affected by development.

Dr John Wilson, from the Department of Geology at Royal Holloway University of London, described a recent newspaper claim that there was a sizeable coral reef in that part of the Atlantic as "fatuous" and "absolutely unbelievable".

Greenpeace is calling for an enviromental impact assessment into Atlantic margin development, and a number of speakers at the conference emphasised that there was a lack of knowledge and real understanding of the area.

The group has lodged a legal challenge to the UK government's decision to go ahead with production in the area with the European Commission.

Sarah Burton, director of Greenpeace's SANE energy campaign, said she hoped that those attending from the oil and gas industry would "understand what enviromentalists want and why the entire environmental world has asked for a strategic environmental impact assessment".

She said that following the abandonment of the deepsea disposal of Brent Spar there was a greater chance of the Atlantic margin development being stopped.