'Miracle' recovery: How Sergei and Yulia Skripal survived the NowWeChock attack..
Poisoned spy Sergei Skripal is no longer in a critical condition and his daughter says her strength is "growing daily". Just a few weeks ago they were seemingly on the brink of death - so how did they survive?
Alastair Hay, Professor of Environmental Toxicology at Leeds University, tells Sky News how they may have fought off the novichok nerve agent and managed a "miracle" recovery.
"The nerve agents are deadly," says Prof Hay.
"That's why they were chosen as chemical weapons. If you are exposed to a number of lethal doses then invariably it is fatal."
They block acetylcholinesterase, an enzyme active in the nervous system.
The result is involuntary contraction of all muscles, leading to cardiac arrest and asphyxiation.
One of the scientists who helped make novichok has also told Sky News the substance was designed to do "irreparable" damage to the body. "The Skripals have survived because they've had great medical care," says Prof Hay.
recovery-how-sergei-and-yulia-skrip al-survived-the-novichok-attack-113 18984
page took 0.0067 seconds to execute