A wealthy Russian whistleblower suspected of being poisoned vomited strange "greeny yellow" liquid after collapsing in the road within the high security gated community where he lived, an inquest heard.
Businessman Alexander Perepilichnyy, 44, had eaten home-made sorrel soup prepared by his wife and daughter before he went out for a run on the afternoon of November 10 2012.
He was discovered at about 5pm by chauffeur-cum-security guard Neil St Clair-Ford as he drove around the St George's Hill Estate, near Weybridge, Surrey.
Giving evidence, Mr St Clair-Ford said: "I was travelling south along Granville Road past one of the properties where I work and got to the brow of the hill, and over it saw something white lying in the road. It was a bit drizzly, towards dusk, so the light wasn't great.
"I slowed down and saw it was a person. I stopped the car, wondered what it was. Looked around. You have to be a little bit careful because you are trained not to stop the car in case someone wants to kidnap the principal."
He told the inquest he did not know Mr Perepilichnyy but recognised him as a regular jogger he had seen a dozen times struggling to get up the hill, "gasping for breath".
On this occasion, he had collapsed and was lying in the road on his side almost in the recovery position with his knees "braced" together, the witness said.
He was pale, cold and "trembling" and appeared to making a "choking" noise, he said.
Mr St Clair-Ford called his former "Navy special forces" colleague Liam Walsh to help with first aid and ran to a neighbouring house to call 999.
The witness told the court he kept talking to the man in the road, even though he was unconscious but breathing.
On turning him over to carry out CPR, the driver told the court he and Mr Walsh noticed Mr Perepilichnyy had a small cut on his head.
On Mr Perepilichnyy's condition as he lay in the road, Mr St Clair-Ford said: "It was so faint when he made a noise. It was more like a choke. His life signs were very faint."
Robert Wastell, counsel for the coroner, asked: "During this time you were with the man collapsed in the road, do you remember seeing any vomit?"
He replied: "When Liam was giving him mouth-to-mouth he released some vomit into Liam's mouth. When he was lying on the road, there was certainly some drool."
Mr Walsh told the inquest: "It was like bile coming up. It was a similar taste to licking a battery. It was a strange taste. There was no solid in it at all. It was just liquid, a gold colour, greeny yellow.
"Every time I gave him a breath it would come up out of his throat and I got a mouthful each time," he said.
Mr Wastell asked: "Did you suffer any problem with your mouth afterwards? Any blistering or skin coming off at all or any illness?"
Mr Walsh said he did not, but added that there were two strange things he noticed about the scene of Mr Perepilichnyy's collapse.
Firstly, the positioning of his body in the road and, secondly, that he appeared to have fallen straight down and not staggered.
When paramedics arrived, Mr Perepilichnyy had gone into cardiac arrest and showed no signs of life, paramedic Daniel Weller told the inquest.
On the security around the estate, Mr St Clair-Ford said: "Certainly there are some high profile individuals. Many of them don't have bodyguards but have chauffeur-security guards.
"At St George's Hill there are a number of gates. There are two main gates so unless you have a pass you cannot get through the gates.
"Each of the gates have vehicle registration cameras and also have security cameras. There are mobile security travelling around the estate and the manned gates are manned 24 hours a day, seven days a week."
Before his death, Mr Perepilichnyy had been helping specialist investment firm Hermitage Capital Management uncover a 230 million US dollar (£150 million) Russian money-laundering operation.
The court heard that around this time, he appeared to receive threats, his name was on a "hit list" in Moscow and he had taken out millions of pounds in life insurance policies.
The inquest, sitting at the Old Bailey, is looking at whether the married father-of-two was poisoned and if so, who might have had a motive to murder him.
The officer called to the scene of Mr Perepilichnyy's death told the inquest he saw nothing suspicious in the area near the body.
Pc Douglas Pasley said: "I had to make a judgment call and update the control room and my supervisors with regard to the circumstances and part of that was to consider whether there was any foul play involved."
He looked around the area for signs that made him "uncomfortable that anything untoward had gone on" but found nothing.
Robert Moxon Browne QC, for insurers Legal and General, asked if it occurred to the officer to search for the collapsed jogger's water bottle.
He continued: "If the deceased had vomited in the road 100 yards away, is that something your search would reveal?" The officer said it would have been outside his search area.
The officer was also quizzed by a lawyer for Mr Perepilichnyy's family about the reaction of a less experienced colleague to the way his widow was treated when she turned up at the cordon.
When CID refused to allow her in to see her dead husband, he said he had never seen his colleague so upset.
But he added: "It was a very difficult situation. It's a real balancing act. At the time the body had just been worked on by ambulance crew. It was without doubt the right thing to do."