The British government has evidence the Russian state was involved in the radioactive poisoning of dissident Alexander Litvinenko, a hearing into his death has been told.
A hearing ahead of a full inquest due to take place next year was also told on Thursday that Litvinenko had been working with the Spanish secret service as well as with British intelligence.
Litvinenko, 43, died in agony in November 2006 after being poisoned with highly radioactive Polonium-210 in London. British police have identified a Russian agent as the main suspect but Moscow refuses to extradite him.
Hugh Davies, counsel to the inquest, said confidential material submitted by the British government "established a prima facie case as to the culpability of the Russian state in the death of Alexander Litvinenko".
The hearing was told Britain's foreign intelligence agency, MI6, had hired Litvinenko for a number of years and he would regularly meet with an MI6 handler, named only as Martin, in central London.
But he was also working for the Spanish secret service investigating the Russian mafia shortly before his death, it was told.
Both the British and Spanish secret services paid money into a joint bank account he held with his wife.
Ben Emmerson, the lawyer for 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".
Russia had meanwhile indicated it wanted to be an "interested party" at the inquest, the hearing was told.
Thursday's hearing is a pre-inquest review ahead of a full inquest that is due to begin on May 1 next year.
Inquests are fact-finding inquiries held under British law to examine sudden, violent or unexplained deaths. They are not trials and do not apportion criminal or civil liability.
British police have identified Andrei Lugovoi, a former FSB agent, as the main suspect in Litvinenko's murder.
Moscow has refused to extradite him and the case has chilled relations between Britain and Russia for years.