BRITISH intelligence officials believe rogue elements in the Russian secret service may have murdered former KGB spy Alexander Litvinenko, it has been reported.

But as he lay dying in agony, poisoned by a radioactive material, Mr Litvinenko insisted he was an "active case" for Russian intelligence and named a senior Kremlin agent as responsible for targeting him.

As British police prepared to fly to Moscow to interview two Russians who spoke to Mr Litvinenko on the day he was poisoned, a senior figure at the International Atomic Energy Agency told The Observer the murder was an organised operation. The ability to obtain the radioactive isotope polonium-210 — most likely from a nuclear facility — and the knowledge needed to use it meant that a lone assassin could not have killed Mr Litvinenko, the IAEA figure said.