Russian security service agents raided BP’s offices in Moscow for the second time in two months, raising concerns that it is coming under mounting pressure ahead of an ownership shake-up of its oil venture, TNK-BP.

TNK-BP, which is 50 per cent-owned by a group of Russian billionaires, has been the target of speculation that it could be a takeover target of Gazprom, the state-controlled energy group. TNK-BP’s Russian owners say they are not looking to sell.