Overseas gas imports will be used to heat about half of Britain’s houses this winter, the highest proportion on record, due to a sharp drop in production from the North Sea, according to the National Grid.

Gas production from the UK sector of the North Sea is likely be 6% less this year compared to 2008-09, according to the National Grid’s annual Winter Outlook report.

This will force Britain to import 50% of its gas from Qatar, Norway, Algeria and Trinidad, a steep rise from 27% in 2007.

Owner of British Gas, Centrica, said that the UK’s ageing gas fields are no longer capable of coping with local demand.

Centrica said that under the current trajectory, Britain will have to import 75% of its gas by the year 2015.

The National Grid said that the drop in production would compel Britain to import large amounts of liquefied natural gas (LNG) by ship.

The group anticipates that nearly 40 million cubic metres of LNG would need to be imported every day to Britain during this winter, which represents 10% of peak winter demand. This will be four times more than the ten million cubic metres imported in 2008.

Additional imports will be made using pipelines from Norway and Holland.