2006 Igor Ponomarev
A Russian diplomat who died in London just 48 hours before Alexander Litvinenko was poisoned. He was due to meet investigators looking at Russian state links to organised crime, but collapsed and died after complaining of extreme thirst.
2006
Alexander Litvinenko
The former KGB officer died after drinking tea laced with radioactive polonium-210. A British public inquiry concluded his murder had probably been directly ordered by Vladimir Putin.
2007
Yuri Golubev
The co-founder of the oil giant Yuko was found dead in 2007 shortly after returning from a trip to Moscow.
2008
Badri Patarkatsishvili
A businessman and politician found dead at his Surrey mansion in 2008. He had raised fears of an assassination plot, but no signs of foul play were found and police closed the case.
2010
Gareth Williams
A former GCHQ codebreaker on secondment to MI6 found dead locked inside a sports bag at his flat.
2010
Paul Castle
A polo-player and friend to the Prince of Wales who leapt to his death in front of a train. An associate said at the time he owed “a lot of money to the wrong people”.
2012
Alexander Perepilichnyy
The businessman fled Russia after after lifting the lid on a $230 million tax fraud by corrupt Russian government officials and died of a heart attack while out jogging in Surrey in 2012. Police and his wife do not suspect foul play, but an inquest heard his stomach contained traces of a rare plant poison.
2012
Robert Curtis
Curtis, a property tycoon, threw himself in front of a train in 2012. Was said to be suffering from debts and depression.
2013
Boris Berezovsky
The Russian oligarch fled to Britain after falling out with Vladimir Putin and lived under tight security. He was found hanged at his Surrey mansion in 2013, but a coroner recorded an open verdict.
2014
Scot Young
A property developer and friend of Berezovsky was found impaled on railings below his central London flat. Young represented Berezovsky in business trips to Russia and was in contact with mafia figures.
2015
Johnny Elichaoff
A friend of Scot Young and the former husband of TV presenter Trinny Woodall fell to his death from a West London shopping centre a month after Mr Young died.
2016
Dr Matthew Puncher
A British scientist who discovered proof Alexander Likvinenko had been poisoned was found dead with stab wounds in 2016. A coroner concluded his death was suicide.
Gareth Williams had a Clinton connection, as I recall.