According to The Guardian newspaper, the British Government is gathering geographical data and preparing a submission to the UN to claim seabed up to 350km offshore into the Southern Ocean.

The planned submission is expected to be closely watched by Australia and other countries with claims on Antarctica, and could trigger competing claims.

Australia, Britain and several other countries signed a treaty in 1959 agreeing that no new claims will be asserted.

The environmental protocol to the Antarctic treaty, agreed in 1991, prohibits mineral-related activity other than for scientific research.

International interest in exploiting the areas around the north and south poles is growing as global warming opens up their long-frozen oceans and as the major economies need new energy supplies.

Earlier this year, Russia was criticised for making claims beneath the Arctic Ocean, while France submitted a claim to thousands of square kilometres around New Caledonia, in the Pacific.