The wife of a Kremlin critic in hospital with major organ failure has told Sky News that those in charge of the Russian system are responsible for his suffering.

Vladimir Kara-Murza – a 35-year-old Cambridge University graduate – fell ill last Thursday and spent the next six days in a medically-induced coma.

Doctors believe he was poisoned by an unidentified toxin – although medics in the Russian capital say they have no idea what it is.

His wife believes that he has paid a heavy price for participating in opposition politics in Russia.

Yvegenia Kara-Murza said: I just think that it’s the whole situation that the Russian government – the current Russian regime creates in the country.

A committed democrat, a vociferous critic of the President Putin and the father of three children, he has been living in exile and was supposed to fly back to the US the day he was taken to hospital.

The former journalist is now coordinator of opposition party Open Russia, backed by former oil baron Mikhail Khordokovsky.

Reuters His views on democracy and human rights have made him unpopular in some quarters It seems likely that two separate attempts on his life have now been made – and there is no greater mark than this of the modern Russian dissident.

Mrs Kara-Murza returned from the family home in the US and has sent off his blood-work to laboratories in France and Israel. On Wednesday, for the first time, she told Sky News that there were grounds for hope.

He is doing better, he is off certain machines that used to give him life support. His heart is working much better, his kidneys are functioning. He’s awake – fully conscious but a little bit hazy.

The democratic activist previously fell gravely ill in 2015 when he collapsed during a routine appointment with colleagues. Doctors blamed an unknown toxin for the sudden failure of his lungs, liver, and kidneys.

Mr Kara-Murza reckoned he was lucky to be alive after that apparent attack.

The doctors told my wife I only had a 5% chance of survival, he said.

The activist was well aware that his views on democracy and human rights made him distinctly unpopular with a wide range of people.

Sky News joined the former journalist on a boat on the Moscow River last summer as he introduced Open Russia candidates competing in parliamentary elections in 2016. He told us he knew he was running a risk.

I think the best thing this regime would like for us to do is to give up and run away – and we’re not going to give them that pleasure, he said.

As he spoke, a dozen-or-so police officers and members of the security services boarded the Open Russia charter through a hatch at the back and proceeded to keep a close eye on Open Russia’s parliamentary event.

As the activist now fights for his life a second time, his wife told Sky News that she will remain at his bedside, for as long as it is necessary.

he is my husband and I will stay. He is man of principles – and democracy and they’ll endure too, she said.