British utility SSE has signed a six-year gas supply deal with Norway's Statoil for 500,000 therms (1.4 million cubic metres) of gas a day, SSE said on Friday.

The contract, which will start on Oct. 1, 2015, amounts to around 6 percent of SSE's average daily gas demand, the company said in a statement.

Terms of the deal were not disclosed but SSE said it will secure gas for the company at "prevailing market prices and conditions".

Statoil sells three-quarters of its gas at spot prices, Statoil's head of gas sales and trading told Reuters in an interview in August.

Statoil is Europe's second-biggest gas supplier behind Russia's state-controlled Gazprom, but its importance has grown since the Ukraine crisis increased the risk of a disruption to Russian gas flows via Ukraine.

Russia supplies around a third of Europe's gas needs and typically around half of this is transported via Ukraine.

Since September, Gazprom has sent less-than-requested deliveries to Poland, Slovakia, Austria and Hungary after the European Union began sending gas to Ukraine.

The European Commission hopes to broker a deal to resolve the standoff after progress was made at a meeting between Ukraine, Russia and Europe's energy ministers at the end of September.

Britain imports around 15 percent of its gas demand from continental Europe, and a large portion of this volume will have originally been imported from Russia.

Europe's utilities are increasing looking for long-term deals to protect them from any supply disruptions or price shocks in the gas market.

Britain's biggest utility Centrica will this month begin receiving gas from Gazprom under a deal signed in 2012 to import 2.4 billion cubic metres (bcm) of gas over a period of three years.

Statoil also has a deal, signed in 2011, with Centrica to supply 5 bcm of gas a year from 2015 to 2025.

(Aditional reporting by Henning Gloystein, editing by William Hardy and David Evans)