
A Whitehall source told The Sunday Telegraph that, while no "smoking gun" linking the Putin government to the poisoning has yet emerged, circumstantial evidence does point towards the involvement of the FSB.
According to the source, the FSB, which replaced the KGB, has been "emboldened" in the past eight months as a result of laws passed by the Russian parliament to allow state officials to carry out overseas assassinations.
So far this year, Russian agents have carried out at least two such assassinations - shooting dead one victim in Estonia and another in Chechnya. The role of the FSB in both murders has been confirmed to this newspaper by a Whitehall source.
Referring to the Litvinenko murder, the source said: "Logic dictates that there must have been state sponsorship behind this attack. All the circumstantial evidence seems to point to the FSB..."
MI6 believe the Polonium 210, which killed former Russian spy Alexander Litvinenko, could have come from China. It is one of the few countries - the United States is another - with the specialist laboratory to produce Polonium 210 as a deadly weapon. It is normally used in the Chinese space programme.
MI6 agents in Moscow believe a minute quantity of Polonium 210 was given to Russia's Federal Intelligence Service, FSB, by the Chinese Secret Intelligence Service.
The FSB has a specialist unit, Department "S" (Special Operations), that is now thought to have carried out the murder of Litvinenko.
The Russian President, Vladimir Putin, worked in Directorate S before he became chief of the KGB. During that time he developed close ties with Chinese intelligence.
Oleg Gordievsky, a former London station chief of the KGB before he defected to this country in 1985, claimed last week Litvinenko could not have been murdered "without the express approval of the president".
A former director of Department S, Alexander Kouzminov, said: "The killing could only have been carried out by operatives of Department S secretly deployed in the West. They have assumed names and well-prepared cover stories and often masquerade as citizens of Western countries".
He claimed the new poison could have entered Britain through "the Volna Channel. This highly secret route, often using diplomatic channels, had been set up in Putin's KGB days to transport biological materials to a country where they were to be used".
Meanwhile, The People's Daily reported:
"The Tianwan nuclear power plant, a major Sino-Russian project now under construction in Lianyungang, a port city in East China's Jiangsu Province, is an example of collaboration in the use of nuclear power for peaceful purposes.
Jiangsu media reported that the first unit of the plant started generating electricity last month; while Russian media said it would reach full capacity next month.
Wen said the strengthening of the Sino-Russian strategic partnership is essential as the development of the two countries as well as global peace and development require it.
Wen also noted that the two countries have co-ordinated well in resolving some sensitive and complicated international issues". End of quotation.
KC