Britain will stop setting North Sea oil prices.

Analysts said the move, which takes effect Monday, had been expected and should have little immediate impact on oil prices but that, if markets start slumping again, it will be more difficult for the Organization of Petroleum Exporting Countries to resist cutting its prices. Britain is not a member of the cartel but competes for sales with Nigeria, which is an OPEC member. British National Oil Corp., the state-owned trading company, has told oil producers that it will no longer regularly set an official price for oil.