Britain will begin this year to import gas from Russia under a formal contract for the first time, just as European calls to loosen Moscow’s grip on energy supply mount because of the crisis over Ukraine.

The country’s biggest utility Centrica signed a deal in 2012 with Russian state-controlled Gazprom to import 2.4 billion cubic metres of gas over a period of three years, and the supplies will begin flowing in October.

Russia is Europe’s biggest supplier of gas, providing around a third of the continent’s needs, and some of this has previously reached Britain from continental European storage sites.

The exports largely go to central and southeast Europe rather than to Britain, which still has significant domestic reserves and gets most of its imports from Norwegian pipe­lines or liquefied natural gas (LNG) shipments from further afield.

With domestic production falling by around seven per cent a year, Britain has had to find more suppliers to fill the gap. Supplies under this deal will begin flowing into Britain from October, a Centrica spokesman said.

While this is the first direct contractual deal, it is not the first time Britain has used Russian gas to heat homes and fuel power plants. Gaz­prom estimates it sends around 12 billion cubic metres to Brit­ain each year, accounting for around 15 per cent of total UK supplies.

The majority of Russian gas imported into Britain in recent years has been sourced from storage sites in Germany, largely filled with Russian supply.