21:04Russian Fugitive Ex-Businessman Dies in London at 68

Mr Glushkov also had a close friendship with fellow Russian businessman Boris Berezovsky, who came to the United Kingdom in 1999 after falling out with Mr Putin.

Glushkov sought political asylum in the United Kingdom after spending five years in jail on charges of money laundering and fraud, charges he claimed were unsubstantiated.

Mr Berezovsky was also a friend of Russian dissident Alexander Litvinenko, who was poisoned with radioactive polonium-210 in London in 2006.

Glushkov told The Guardian newspaper in 2013 he didn't believe Berezovsky's death was suicide.

He told The Guardian: "I'm definite Boris was killed".

"He told me he was from Georgia and always said how lovely it was".

But it said there was "no evidence to suggest a link to the incident in Salisbury", adding that the death was being treated as "unexplained".

Glushkov continued to investigate the circumstances surrounding Berezovsky's death for some months.

Glushkov was a close friend of another Russian man, Boris Berezovsky, who was granted asylum in the United Kingdom after he faced a jail term in Russia.

Mr Glushkov had worked for various Berezovsky enterprises, including the auto factory AvtoVAZ and flagship Russian airline Aeroflot.

Berezovsky was found dead in March 2013 at his ex-wife's home in Berkshire.

Nikolai Glushkov, 68, was discovered dead late on Monday at an address in Clarence Avenue in suburban south-west London.

He added: "too many deaths [of Russian emigres] have been happening". He was sentenced to eight years in prison by a Russian court for the theft of millions of dollars from Aeroflot when he served as its director in 2017.

The White House on Monday condemned the poisoning of the ex-Russian spy in the U.K."The use of a highly lethal nerve agent on U.K. soil is an outrage".

They were found in Salisbury, around two and a half hours from London.

Relations between Britain and Russian Federation have been strained since the murder in London of former KGB agent Alexander Litvinenko, who died in 2006 after drinking green tea laced with radioactive polonium-210.

Ms Rudd said the Government takes seriously allegations that the deaths, dating back to 2006, may have some links to Russian Federation.

Vanessa Coleman