Russian billionaire Mikhail Fridman has yielded to growing pressure from the UK authorities to sell a sizable portion of his North Sea gas assets to comply with the country's rules.

Fridman's LetterOne investment company is close to hiring advisers to seek for buyers for a dozen North Sea gasfields, the Financial Times reported, citing people familiar with the plans.

Sources, however, noted that no final decision has been taken and that Fridman's L1 Energy fund is reviewing its options.

Falling oil prices are also expected to have prompted the billionaire to take the decision, which if successful, would help avoid a high-profile legal battle with the British government.

Earlier in March, LetterOne completed the purchase of the Dea oil and gas company subsidiary from Germany's RWE in a deal worth €5.1bn (£3.7bn, $5.4bn). The deal raised concerns for the British government, which was afraid that if Fridman and his company are put on the sanctions list it may jeopardise field development in the North Sea.

On 4 March, London gave LetterOne a week's time to prove that they have the right to keep the deposits in the North Sea, or sell them. Britain has been the first Western government to intervene in a corporate deal over further Western sanctions against Russia.

LetterOne earlier threatened to seek a judicial review if the Dea deal is blocked, but later decided to avoid the risk of being embroiled in a court battle.

Fridman looked ready to press on with building an international energy business, even without the North Sea fields, which account for up to 5% of the UK's total gas output, the Financial Times added.