A company owned by Ukraine’s richest man, Rinat Akhmetov, revealed on Thursday it was one of three financial backers for a strategically important hydrocarbon project whose fate was cast into doubt this week by Kiev’s prime minister.

DTEK, Mr Akhmetov’s energy holding, revealed at a press conference in Kiev that it held a quarter interest as financial backer in a Black Sea exploration project led by Houston-based Vanco Energy Company.