A Russian businessman found dead near his home had a rare poison in his stomach, a coroner's court heard.

Alexander Perepilichnyy was discovered in Granville Road, part of St George's Hill, on November 10, 2012, before being pronounced dead half an hour after an ambulance arrived.

The death was originally thought to be non-suspicious, but an inquest was called to investigate the facts.

June 7 2013: 'No suspicious circumstances' around Russian's death in St George's Hill

He had moved to Britain three years previously after an alleged falling out with a Moscow crime syndicate and it emerged he was helping Swiss authorities in a major corruption investigation.

The 44-year-old had also given evidence against people linked to the 2009 death of anti-corruption lawyer Sergei Magnitsky. Mr Perepilichnyy was the fourth person linked to that case to have died in strange circumstances.

A pre-inquest hearing at Woking Coroner's Court on Monday, May 18, heard he had ingested gelsemium, a toxic plant only found in China, leading Coroner Richard Travers to adjourn the four day inquest.

The court heard tests carried out by botanist Professor Monique Simmonds of Kew Gardens found a chemical in Mr Perepilichnyy's stomach that could have only come from gelsemium. Poisoning from this plant can make it appear the victim has died of a heart attack.

Two post-mortem examinations were carried out on November 14, and November 30, 2012, but did not find a cause of death and police did not believe a third party was involved in his death.

A Surrey Police spokesman said: "Following today’s hearing, the coroner has asked for some additional work to be carried out to seek clarification on some areas.

"Surrey Police, along with all other interested parties, will continue to cooperate fully with the Coroner throughout the process."

The inquest into Mr Perepilichnyy's death is expected to be heard in September.