The poisoning of outspoken former Russian spy Alexander Litvinenko is a story with as many twists and turns as a novel.
Litvinenko was killed in London in November 2006 when two Russian spies dropped a small dose of radioactive polonium-210 in a cup of tea he was drinking at a meeting with them in a London hotel.
Litvinenko had more than one paymaster. He was in the Russian espionage group the Federal Security Service (FSB), which took over from the feared KGB.
Russian president Vladimir Putin was the head of the FSB at the time, and Litvinenko found himself marginalised and became a critic of the Moscow government.
He fled to London and is rumoured to have changed sides and joined MI6.
Putin blamed for murder
Shortly before his death, Litvinenko published an article on a Russian web site claiming Putin was a paedophile and that this was widely known in the upper echelons of the FSB and that films proving his crimes were stored in a vault by the security service.
The allegation was never proved, but on his deathbed, Litvinenko claimed Putin was responsible for his demise.
Eventually, the British government was persuaded to initiate a public inquiry into the murder and the report claims Putin ‘probably’ sanctioned the death of Litvinenko.
Moscow denies the allegations and calls them lies.
While Mrs Litvinenko calls for the expulsion of suspected Russian spies from London and sanctions against Moscow, the British government seems powerless to act.
Ticking off for ambassador
Russia is already suffering from sanctions resulting from the annexation of The Crimea from Ukraine and the country’s athletes are banned from international competition due to a doping scandal.
The Foreign Office will no doubt call the Russian ambassador in for a ticking off, but that’s about the limit of what can be done.
Even Prime Minister David Cameron agreed Britain has to have a diplomatic relationship with Moscow, mainly due to both countries intervening in the war in Syria.
International arrest warrants are out for the two alleged killers, Andrei Lugovoi and Dmitry Kovtun, while their assets outside Russia are frozen. The likelihood of them coming to London for a trial is small and the Russian government refuses to extradite them.