There is "no link whatsoever" between the announcement of a public inquiry into the death of former spy Alexander Litvinenko and the current tensions with Russia over the Ukraine, according to David Cameron's official spokesman.
The probe will begin on July 31st and is planned to be complete by the end of next year, they said, adding that it will hold most of its hearings in public, although it could go into closed session if national security was put at risk.
Under the Inquiries Act, Sir Robert Owen who is leading the investigation will have the power to demand the production of witnesses and papers within UK jurisdiction, including agents and documents from the security and intelligence services.
However, he has no such powers in relation to evidence from Russia.
More top news
Mr Blavatnik, whose empire includes the Warner Music Group, has an estimated fortune of £13.17bn according to the Sunday Times Rich List.
Find out what to expect from the weather if you are running in the big race in London or watching from the sidelines.
It will be a soggy start to the weekend and temperatures will drop making it feel colder than in recent days.