A couple who are in a critical condition after being discovered unconscious at a house in the Wiltshire town of Amesbury were exposed to novichok, Scotland Yard has confirmed.
Novichok was used to poison ex-Russian spy Sergei Skripal and his daughter in Salisbury in March - an incident that sparked a major diplomatic rift between the UK and Russia.
Authorities initially believed that Dawn Sturgess, 44, and Charlie Rowley, 45, became unwell as a result of using heroin or crack cocaine from a contaminated batch of drugs. However, the Metropolitan Police’s assistant commissioner for counterterrorism, Neil Basu, has now confirmed that the couple were exposed to novichok, calling it a “significant development” in what has become a “major incident”.
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Police have since cordoned off a number of sites in Amesbury, just eight miles from Salisbury, to investigate the poisoning and begin a major clean-up operation.
But what exactly is novichok, and why is it so dangerous?
Novichok is a series of highly toxic nerve agents, each with a different potency, first developed in the former Soviet Union in the 1970s and 1980s, Reuters reports. The specific circumstances of their creation remains shrouded in secrecy.
The name novichok means “newcomer” in Russian, in a nod to the fact that it heralded a major breakthrough in the power of such chemical weapons.
Novichok agents bear a “slightly different chemical composition than the more commonly known VX and sarin poison gases”, the news site says, but are believed to be five to ten times more lethal.
The lethal nerve agents are believed to have been developed in an attempt to circumvent the Chemical Weapons Treaty (CWT), according to research news site ScienceDirect. Chemical weapons were, and always have been, banned on the basis of chemical structure, but a new chemical agent with a new structure was not subject to past treaties.
Moscow has never declared the existence of novichok agents to the Organisation for the Prohibition of Chemical Weapons (OPCW), which oversees the CWT.
How does novichok work?
Novichoks are known as binary agents, because they only become lethal after mixing two otherwise harmless components.
They are dispersed as an ultra-fine powder, rather than a gas or vapour, and can be inhaled, ingested or absorbed through the skin. In some attacks they have been smeared on door handles or other unassuming places.
As a result, the police have advised members of the public in Salisbury and Amesbury not to pick up any unfamiliar objects where possible, the BBC reports.
Andy Oppenheimer, a biological and chemical specialist, told Sky News that the nerve agent could have been brought into the UK through an airport.
“These things can evade detection if they are very small amounts and very well shielded,” he said. “This chemical may have come through an airport, we really don’t know yet.”
What are its effects on humans?
Like many nerve agents, novichoks works by inhibiting the enzyme cholinesterase, which s normally responsible for degrading a chemical in the body that stimulates muscular contraction.
The resulting controlled muscle contractions can cause paralysis, breathing problems, convulsions, and cardiac arrest.
Novichok agents do not degrade quickly in the environment and it is still not fully understood how they work, The Guardian says.
Atropine can be used as an antidote to all nerve agents but the medication needs to be administered as soon as possible.
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