A leading member of a Russian opposition party has told how he believes he was poisoned in a "politically motivated" attack.
"Within the space of 10 to 15 minutes I went from feeling normal to feeling horrible," said Vladimir Kara-Murza, deputy leader of PRP-Parnas. "I was having palpitations, a massive heart rate, sweating, vomiting, losing consciousness."
Kara-Murza was halfway through a routine appointment with two colleagues in Moscow last May when the sickness struck.
He does not know when or how the poison entered his system, or whether he ingested it with food or liquid. As he lapsed into unconsciousness, he would not know that he spent the next 24 hours being shuttled between three hospitals as doctors struggled to work out what was wrong with him.
"My vital organs began to fail, one by one: lungs, liver, kidneys, one after another like a cascade," he said. "The doctors told my wife I only had a five per cent chance of survival."
In the end, Kara-Murza was saved by doctors at Moscow's Pirogov hospital. They diagnosed him with "acute intoxication of unidentified origin" - some kind of poisoning - and put him on haemodialysis to clean his blood.
After six months of rehabilitation in the United States, Kara-Murza is back back in Russia but, at the age of 34, he walks with a cane because he has yet to regain full control of his left side.
But he has two aims: to run an anti-Kremlin political campaign, and to hunt down the people he believes tried to kill him.
Kara-Murza has submitted a formal request for Russia's Investigative Committee, the country's version of the FBI, to open an inquiry into what he believes is a case of attempted murder motivated by political hatred.
"I have no doubt that this was a deliberate poisoning, that it was intended to kill, and that it was motivated by my political and public activities in the Russian opposition," he said.
Kara-Murza believes he is the latest in a series of activists, politicians and journalists - all critics of President Vladimir Putin - to have been targeted in recent years.
In his own case, he does not know who poisoned him, or on whose orders. He speculates that he may have been targeted for his association with Mikhail Khodorkovsky, the exiled former oligarch, whose Open Russia foundation he works for and who paid for his treatment in the US.
Another possible motive, he said, was his role in campaigning for the Magnitsky Act, a US law that imposes targeted sanctions against Russian officials suspected of involvement in human rights abuses.
-Telegraph Group Ltd