Andrei Lugovoi: Alexander Litvinenko murder suspect speaks out
As the Prime Minister David Cameron prepares to travel to Russia, it has emerged that no British government minister or diplomat has spoken to Vladimir Putin since 2007.
Relations went into sharp decline following the murder in London of Alexander Litvinenko in 2006.
Investigators in the UK blamed the murder on the former KGB member Andrei Lugovoi, who they want extradited.
The BBC has been to Russia's far east where the suspect, currently a member of the country's parliament, continues to deny carrying out the crime.
Daniel Sandford reports.