Fears that the UK has become a battleground for Russian vendettas have been reignited after the security services publicly warned of an assassination plot against a high profile Chechen exile.
Akhmed Zakayev, a dissident Chechen politician and friend of the actress Vanessa Redgrave, is on a list of targets supposedly wanted dead by his political rival, the Chechen president Ramzan Kadyrov, according to court documents.
MI5 and the Home Secretary are involved in a legal battle to expel a Russian, known only as E1, who they believe would "facilitate" the murder of Zakayev. MI5 is alleged not to have told the exiled Chechen prime minister that he was the target of an assassination plot by the man they are trying to deport as a threat to national security.
The revelations come in the wake of the attempted assassination of the wealthy Russian banker, German Gorbuntsov, who remains critically ill after being shot outside his London home.
Zakayev was a friend of Alexander Litvinenko, the former KGB officer killed with radioactive poison in London 2006. MPs warned last night that Britain was becoming a Russian battleground amid growing concerns about the number of exiles who pose a serious security risk to the UK. It is a pressing concern for security forces as the Olympics pose a historical terrorist opportunity.
Zakayev, a former actor known as Chechnya's Laurence Olivier who went on to command rebels in the war with Russia, was granted refugee status in Britain in 2003. Russian demands that he be extradited to face terrorism charges were rejected, on the grounds that he would be at risk of torture.
Zakayev is close friends with Redgrave, who put up £50,000 to secure bail during his extradition battle. In court documents, reported by The Sunday Telegraph, the judges said: "Kadyrov, who had been responsible for the assassination of a number of his opponents, has a black list of individuals, some of whom he wished to have assassinated, and ... the exiled Prime Minister of Chechnya, Akhmed Zakayev, a refugee living in the UK, was believed to be on this list."
MI5 said the attack on Mr Zakayev "would be likely to be facilitated through [E1] who would be well placed to provide valuable information".
MI5 said E1 was involved in the killing of Umar Israilov, a former Kadyrov bodyguard, turned vocal opponent of the Chechen leader. He was shot dead in Vienna in 2009. Zakayev told The Sunday Telegraph that "there are more Russian spies in Britain today than during the Cold War".
Patrick Mercer, a Conservative MP and former shadow Minister for Homeland Security, said: "We know there are a large number of espionage operators working out of modern Russia in a number of western countries. The funding for these, as far as we can see, from the interior and foreign ministries, has increased over the past 10 years or so.
"There are a large number of Russians and people from the former Soviet Union living in London which has become a Russian battleground by proxy.
"It would be wrong to think that the Russian intelligence officers were directly concentrating on UK interests; they are mainly here concentrating on their own exiles.
"The UK has become the playground rather than a player in all of this. We cannot become a battleground for other nations to carry out their vendettas and other intelligence battles.
"Diplomatic efforts must of course be used, but our intelligence services must be completely rigorous about dealing with all enemies, including foreign intelligence services, under British law."