Relatives of British deep-sea divers killed in the North Sea during the boom years of oil exploration are to seek compensation from the Norwegian Government which is expected to run to millions of pounds.

The families of seven British divers — all of whom died between the 1960s and 1980s as the scramble for oil intensified in the North Sea — are expected to submit formal applications for compensation over the next few weeks.

In a blow to Norway's international image as a champion of human rights, they claim that they have been forgotten by Oslo and that their loved ones died because of factors — including faulty equipment and excessive working hours — that were ultimately the responsibility of the Norwegian Government as owner of the oilfields.

The families also hope to join a class action lawsuit against the Government by 24 former divers who claim that they were treated as “human guinea-pigs” and sent to extreme and dangerous depths, sometimes as low as 1,300ft (396m), more than twice the current safety limit.

The court case has raised awkward questions about Norway's pursuit of oil in the early years of North Sea exploration. The plight of the “forgotten divers” and their families, has been highlighted in articles by the Norwegian Dagbladet newspaper. Of 17 fatalities in the Norwegian sector of the North Sea between 1967 and 1987, 11 were British and the rest Norwegians and Americans. It is believed that the family of only one dead British diver has been compensated by the Norwegian Government.

The North Sea Divers Alliance (NSDA) has contacted relatives of seven of the 11 dead Britons, but are still seeking the remaining four.

Although the Norwegian Government has admitted political and moral responsibility for the “pioneer divers”, who worked in the North Sea from 1965 to 1990, it has denied legal responsibility, allowing it to rebuff large-scale compensation suits. In 2004 the Norwegian parliament authorised a payment of Kr2.5million (£240,000) for each of about 200 divers, but the NSDA says that this does not go far enough and has excluded most relatives of foreign divers until now.

Tom Wingen, 54, spokesman for NSDA, said: “To apply for compensation you need a Norwegian identity number but most of the relatives of foreign divers were never given these.”

Among those seeking compensation is Ruth Crammond, 57, whose husband Bill was killed in November 1983 with four other divers, two of them British, on the Byford Dolphin oil rig.

Mrs Crammond, from Dalgety Bay, Fife, who had always believed that her husband was to blame for the deaths by opening a clamp before the chamber containing the divers had depressurised, found through a report obtained by the NSDA last month that the real cause was faulty equipment.

Clare Lucas, 32, from Huddersfield, West Yorkshire, whose father, Roy, was also killed in the Byford Dolphin accident, said: “I would go so far as to say that the Norwegian Government murdered my father because they knew that they were diving with an unsafe decompression chamber.”

The first witnesses of the case before Oslo City Court will be called today.

DEEP-SEA TREASURE

— Norway discovered oil on its continental shelf in 1971

— It is the world's third-largest oil exporter

— Oil production peaked in 2000 and has since slowed, although GDP growth increased in 2004-07 because of higher oil prices

— Aware that income from oil will slow, the Government set up the Government Petroleum Fund to invest energy profits, now valued at $250 billion

— Most Norwegians are actually served by hydroelectric power

Sources: CIA World factbook; Times archives

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