UK company Centrica has bought 67% of the two York gas fields in the southern area of the North Sea, boosting its holding to 90% of the fields. Centrica paid $31.5 million (£22 million) to US-based independent Hess for the stake. The purchase adds to Centrica's existing to the 23% stake in the York fields, acquired when it bought the nearby Rough storage field in 2003.