PRESS ASSOCIATION -- The widow of murdered former KGB agent Alexander Litvinenko has called on David Cameron to use his upcoming trip to Russia to demand justice for her husband.
Mr Cameron is the first British Prime Minister to visit Russia since Mr Litvinenko was murdered in London in 2006 - an incident which sent relations between the countries back into the deep-freeze.
Moscow has refused a long-standing British request to extradite the prime suspect in the case, Andrei Lugovoy, a former KGB officer who is now a member of the Russian Parliament.
Mr Litvinenko died in hospital at the age of 43 after suddenly falling ill and was found to have been poisoned with radioactive polonium-210. He had been a prominent critic of Russian prime minister Vladimir Putin.
His widow Marina said it would be "very upsetting" if Mr Cameron failed to raise the case during his visit this weekend, when he will meet Russian president Dmitry Medvedev.
Mrs Litvinenko told The Times: "They have to find a solution to make justice, but not in Russia. This kind of murder was a kind of terrorist attack because radioactive material was used in London and damaged many lives, not just my husband."
Mr Cameron's trip to Russia is the first by a UK leader since Tony Blair attended the G8 summit St Petersburg in 2006, at a time of warm relations between London and Moscow, which had seen a state visit by Mr Putin in 2003.
The Prime Minister will be accompanied by a business delegation thought to include Bob Dudley, chief executive of BP, whose Moscow office was raided last week in relation to a legal dispute.