A man suspected of poisoning former KGB agent Alexander Litvinenko has been hired by a Russian production company as a consultant for a TV series on the mysterious murder.

Andrei Lugovoi will advise the director and actors of a miniseries on the circumstances of the murder he allegedly committed. He is suspected of lacing Litvinenko's tea with highly radioactive polonium-210 at a London hotel in 2006.

Lugovoi, also a former Soviet spy, said his expertise had also been requested by some foreign studios, which he however didn't trust.

"I made a conscious decision to turn down all of them because I understood that none of them were able to tell this Russian story truthfully because of a different mentality," he said.

Production company Central Partnership said that Lugovoi provided them with details of his last meeting with Litvinenko and also helped the screenwriter with the script.

Lugovoi was identified by British authorities as one of two Russian men who met with Litvinenko, a vocal critic of the Kremlin, for tea at the Millennium Hotel in Grosvenor Square the day of the poisoning.

Litvinenko died three weeks later. From his deathbed the 43-year-old accused Russian President Vladimir Putin of ordering his murder. Moscow has always denied the claim.

Lugovoi was charged with murder but the Kremlin has refused to extradite him to the UK. He went went on to become a lawmaker with the Liberal Democratic Party in the state Duma where he still sits.

After a lengthy legal battle carried out by Litvinenko's widow, Marina, Britain announced a public inquiry into the ex-spy's death in July.

The development came as relations between London and Moscow grew sour over the Ukrainian crisis and the related downing of a passenger jet.

Lawyers for Litvinenko's family told a pre-inquest hearing that he was working for Britain's MI6 after defecting from Russia when he was killed.