A CORONER will rule today on the mysterious death of a Russian multimillionaire who collapsed and died while jogging near his home in Surrey.

Alexander Perepilichnyy, 44, collapsed in Weybridge in November 2012 after spending the night before his death with his mistress in Paris.

Coroner Nicholas Hilliard QC has been examining whether the married businessman could have been murdered with poison or if he died of natural causes.

The Old Bailey has heard a wealth of evidence that Mr Perepilichnyy had been blowing the whistle on alleged organised crime in Russia.

He had been helping UK-based campaigner Bill Browder's Hermitage Capital Investment £142 million money-laundering operation, the inquest was told.

Speaking ahead of the final Old Bailey hearing, Mr Browder said he had "no hunches".

He said: "I have no idea how this will go. We have been waiting for answers since 2012."

Perepilichnyy, a dad-of-two, was said to have appeared on a hit list in Moscow before his death.

He had taken out £3.5 million of life insurance and applied for another £5 million of policies amid concern to provide for his family, it was claimed.

A month before his death he had fought off a legal challenge by a debt recovery firm allegedly led by a prime suspect in the Alexander Litvinenko poison case, Dmitry Kovtun.

It was claimed an assassin may have wanted to kill him either to silence him or seek retribution and had the means to do it undetected.

Extensive tests have failed to identify any poison in Mr Perepilichnyy's body, although experts could not categorically rule out a toxin or even a nerve agent such as Novichok.

It was alleged an undetectable poison could have been used, or that the opportunity to identify it was lost in the days after his death.

Surrey Police have faced heavy criticism from Hermitage over its handling of the investigation.

Mr Browder, who describes himself as Vladimir Putin's "number one enemy", cited a "horrible lack of response" to a letter in 2012 alerting police to the organised crime connection.

He said: "We asked them to investigate his death as a potential murder and asked them to as quickly as possible secure the evidence and look for toxicology tests, based on the murder by poison of Alexander Litvinenko. The police didn't respond."

Not only were the contents of Mr Perepilichnyy's stomach thrown away, it also emerged that data on his computer had been lost.

It included alleged evidence of half-a-billion dollar transactions, threats and links to the money laundering case, the inquest was told.

On December 10 2012, Assistant Chief Constable Olivia Pinkney identified missed opportunities to alert senior management of issues surrounding the death, including a referral to Special Branch.

The coroner resisted calls for disclosure on whether Mr Perepilichnyy was in contact with British intelligence after a Government application for secrecy in the national interest.

Detective Superintendent Ian Pollard, of Surrey Police, has maintained there were no signs of "third party involvement or foul play".

The night before his death, Mr Perepilichnyy had been sick after a meal out at a fish restaurant in Paris with his ex-model lover Elmira Medynska, 28, the inquest heard.

While a post-mortem examination failed to identify a natural cause, it has been claimed the most likely explanation is sudden arrhythmic death syndrome.

Interested parties, including life insurers Legal and General, Hermitage, widow Tatiana Perepilichnaya and Surrey Police will reconvene at the Old Bailey on Wednesday to hear Mr Hilliard's findings.

In the absence of firm evidence that Mr Perepilichnyy was unlawfully killed, the coroner can reach an open conclusion or record death by natural causes.