Evidence found by the British Government has shown the Russian state was involved in the murder of former spy Alexander Litvinenko, a pre-inquest review has heard.

Mr Litvinenko, 43, died in November 2006 after he was poisoned with polonium-210 while drinking tea at a meeting, allegedly with two Russians - former KGB contacts Andrei Lugovoy and Dmitry Kovtun - at the Millennium Hotel in London's Grosvenor Square.

Prosecutors named Lugovoy as the main suspect in the case but Russia has refused to extradite him to the UK for questioning.

Hugh Davies, counsel to the inquest into Mr Litvinenko's death, said assessments of confidential material submitted by the British Government had "established a prima facie case as to the culpability of the Russian state in the death of Alexander Litvinenko".

Ben Emmerson QC, representing Mr Litvinenko's wife Marina, said the inquest should also consider whether MI6 failed in its duty to protect against a "real and immediate risk to life".

Mr Litvinenko had been hired by MI6 for a number of years and was working with the Spanish secret service investigating the Russian mafia shortly before his death, a pre-inquest review at Camden Town Hall, in London, heard.

He would regularly meet with an MI6 handler, named only as Martin, in central London and was paid by both the British and Spanish secret services into a joint bank account he held with his wife, the hearing was told.

The Russian Federation has now indicated its wish to become an interested party in the inquest, which is to be held on May 1.