THE oil giant BP will pile the pressure on Britain’s stretched gas supplies tomorrow when it shuts down a large gas network in the North Sea.

The Southern North Sea pipeline system brings gas ashore from a collection of fields. The closure for maintenance will last a week and take 1% of domestic UK supplies offline at a time of near-record demand. BP declined to comment.

The shutdown highlights Britain’s growing dependence on imports as North Sea reserves dwindle. Since the beginning of the month, four ships from the Middle East and Africa, each with enough gas to supply the UK for eight hours, have unloaded at terminals at Milford Haven in Wales and the Isle of Grain, Kent. A fifth is set to dock tomorrow.

Two undersea pipelines connecting Britain to continental suppliers have also been flowing at near capacity. Britain will this year import 50% of its gas supplies. By 2015 that proportion is expected to rise to 75% as domestic supplies dry up.