LONDON - British Gas announced Tuesday it will increase the energy prices for standard tariffs by an average of 5.5 percent in May, affecting 4.1 million households in the United Kingdom.

The company attributes the price hike to rising wholesale energy and government policy costs.

The increase will take effect from May 29 and means British Gas will be the first of the major suppliers to raise prices this spring.

The price hike translates to an increase of 60 pounds ($84.96), in customers' energy bills for customers paying the standard variable tariff, but will not affect the 3.7 million customers who are on fixed-term contracts, prepayment meters or classed as vulnerable.

British Gas cited increased wholesale gas and electricity costs and the price of Conservative Party policies as being behind its latest hike. Centrica, the parent company of British Gas, said its decision has been driven by "rising wholesale and policy costs."

Energy companies have come under pressure over the use of standard variable tariffs, which are often more expensive for customers than fixed-term deals.