Visa applications from Russia are dealt with "rigorously and properly", Downing Street said after reports billionaire Chelsea owner Roman Abramovich's document had not been renewed.
The Government is examining investor visas issued to Russians in the wake of the Salisbury nerve agent attack and the deterioration in relations with Moscow.
Downing Street would not be drawn on the circumstances surrounding Mr Abramovich, stressing: "We don't discuss individual cases."
The Financial Times reported on Sunday that Mr Abramovich's investor visa had expired. John Mann, the 51-year-old's Moscow-based spokesman said it was a private matter and there would be no comment.
There is nothing to say Mr Abramovich's visa situation, where his renewal application is taking longer than usual, is linked to the strain in relations between Moscow and the West.
The Home Office is examining its approach to the Tier 1 investor route - which requires applicants to be prepared to invest £2 million in the UK - following the nerve agent attack on Sergei Skripal and his daughter Yulia in March.
The Prime Minister's official spokesman said: