A Russian whistleblower who died in suspicious circumstances could have been assassinated if he was spying for Britain, an inquest has heard.

American intelligence agencies have no evidence of Russian involvement in the death of Alexander Perepilichnyy, according to a letter from the US Embassy that was presented to London’s Old Bailey.

But lawyers called for information on whether the 44-year-old was working with British security services to be made public.

Coroner Nicholas Hilliard QC has been examining whether Mr Perepilichnyy was poisoned or died of natural causes.

He collapsed and died while jogging near his home in Surrey in 2012. A police investigation found no evidence of murder at the time.

Mr Perepilichnyy, a millionaire financier, moved to Britain from Moscow in 2009 and handed over documents detailing the alleged involvement of senior Russian officials in a $230m (£175m) tax fraud, while helping a Swiss investigation.

An anti-corruption lawyer leading the probe, Sergei Magnitsky, was imprisoned without trial and died in custody in disputed circumstances.

Bob Moxon Browne QC, representing life insurers Legal and General, called on the court to reject a government bid to keep information on its contact with Mr Perepilichnyy secret, by claiming it is in the national interest.

He said: “My concern was always, so far as this PII (public interest immunity) was concerned, around the single issue which is whether or not British police or the government have evidence that Mr Perepilichnyy was prior to his death working for or in contact with British intelligence.”

Police reviewing security of defected Russian spies in UK after Salisbury nerve agent attack

He argued there should be an exception to the rule of neither confirming nor denying contact with security services in this case.

Mr Moxon Browne said the nerve agent attack on former double agent Sergei Skripal “demonstrates the lengths to which the Russian state are prepared to go to make an example or punish people perceived as enemies, traitors or turncoats”.

He added: “For Mr Perepilichnyy, the evidence we have heard arguably if not certainly falls into the same bracket.”

The inquest heard that the public was told of Russian defector Alexander Litvinenko’s role with British intelligence after he too was poisoned with radioactive tea in London in 2006.

Mr Moxon Browne said that any contact between British spies and Mr Perepilichnyy would be “very powerful evidence indeed that he might have been in special danger from those who wish him ill because of the perception he was a traitor or a turncoat or enemy of Russia”.

Skripal attack aftermath – in pictures Show all 15 1 /15 Skripal attack aftermath – in pictures Skripal attack aftermath – in pictures Scene of attack Members of the emergency services in hazard suits fix the tent over the bench where Sergei and Yulia Skripal were found unconscious on a park bench in Salisbury in March 2018. Getty Skripal attack aftermath – in pictures Victim - Sergei Skripal The retired Russian colonel and former double agent for MI6 was in a critical condition in hospital for more than two months after being exposed to novichok in Salisbury. He was given refuge in the UK after being jailed in Moscow for treason. Mr Skripal came to Britain as part of a high-profile “spy swap” in 2010 in which four men were exchanged for ten Russian "sleeper agents" in the US. In this image he is speaking to his lawyer from behind bars in Moscow in 2006. AP Skripal attack aftermath – in pictures Victim - Yulia Skripal Yulia Skripal was struck down by a novichok poison alongside her father Sergei. Facebook Skripal attack aftermath – in pictures Scene of attack A police officer stands guard outside a branch of the Italian chain restaurant Zizzi where the pair dined at before falling ill. It was boarded off whilst investigators worked on the building and later found traces of the chemical weapon within it. AFP/Getty Skripal attack aftermath – in pictures Scene of attack Large areas of central Salisbury were cordoned off by police following the discovery of the Skripals. Traces of nerve agent were also found in The Mill pub. PA Skripal attack aftermath – in pictures Victim - Nick Bailey Detective Sergeant Nick Bailey, rushed to the aid of the Russian ex-spy and his daughter who were targeted with a nerve agent. He was hospitalized after aiding them and didn't leave until three weeks after the attack. Wiltshire Police/Rex Skripal attack aftermath – in pictures Police investigation - Skripal’s home Police believe they were poisoned at home, and detectives found the highest concentration of novichok on the front door of Mr Skripal’s house. Getty Skripal attack aftermath – in pictures Theresa May visits scene of attack Britain's Prime Minister Theresa May spokes with Wiltshire Police's Chief Constable Kier Pritchard near where the Skripal's were found. Britain expelled 23 Russian diplomats over the nerve agent poisoning and suspended high-level contacts, including for the World Cup on March 14. Theresa May told parliament that Russia had failed to respond to her demand for an explanation on how a Soviet-designed chemical, Novichok, was used in Salisbury. AFP/Getty Skripal attack aftermath – in pictures Skripal days before attack Sergei Skripal days before he was exposed to Novichok, that has left him fighting for life. ITV News Skripal attack aftermath – in pictures Police investigation - military involvement British soldiers were deployed soon after the attack to help a counter-terrorism investigation into the nerve agent attack. One of the places they were asked to help out with was Skripal's home and it's surrounding. They were asked to remove a vehicle connected to the agent attack in Salisbury, from a residential street in Gillingham. AFP/Getty Skripal attack aftermath – in pictures Police investigation Personnel in protective coveralls and breathing equipment cover an ambulance with a tarpaulin at the Salisbury District Hospital. AFP/Getty Skripal attack aftermath – in pictures Police investigation The investigation extended to the grave of Sergei Skripal's son Alexander in London Road cemetery. Getty Skripal attack aftermath – in pictures Police investigation The Counter Terrorism Policing Network requested assistance from the military to remove a number of vehicles and objects from Salisbury. EPA Skripal attack aftermath – in pictures Home Secretary visits scene of attack Home Secretary Amber Rudd visited the scene of the nerve agent attack at the Maltings shopping centre on 9 March. Getty Skripal attack aftermath – in pictures Yulia Skripal speaks for the first time Yulia Skripal, speaking for the first time, said she felt lucky to have survived the nerve agent attack in Salisbury which left her fighting for life. Ms Skripal said her life had been “turned upside down” by the assassination attempt. But the Russian national added she hoped to return to her homeland one day, despite the Kremlin being blamed for the attack. Reuters

He questioned whether it would be beyond credibility that Mr Pereplichnyy was “rubbed out” if he was “in the bosom of British intelligence”.

The US government did not ask for secrecy with its own information, submitting a letter rejecting a report by BuzzFeed News claiming that intelligence services believed Mr Perepilichnyy was assassinated on the direct orders of Vladimir Putin or those close to him.

American officials said the article “contains no US Government reporting concerning the death of Mr Perepilichnyy”.

Lawyers for interested parties, the public and press were ejected from court as the coroner heard details about the government’s secrecy application.

Representative Andrew O’Connor QC said the disclosure of sensitive material raised a “real risk of serious harm to one or more public interests”.

Following the Salisbury attack in March, Amber Rudd, the home secretary at the time, launched a probe into allegations of Russian state involvement in up to 14 deaths in the UK.

They include those of Mr Perepilichnyy, the exiled oligarch Boris Berezovsky, the “spy in the bag” Gareth Williams and a British scientist stabbed to death after being involved in the Litvinenko case.

Amber Rudd stressed that investigations and coroner’s inquests at the time “did not discover evidence of foul play” but said the circumstances would be looked at again.

The probe was announced the day after another Russian businessman, Nikolai Glushkov, was murdered at his London home.

Last month, the national security adviser revealed that police were reviewing the security of all defected Russian spies living in the UK.

The inquest into Mr Perepilichnyy’s death is expected to resume later this year.