Novichok was again in the headlines in recent weeks, following news Russian opposition figure Alexei Navalny was poisoned by the nerve agent in August.
Forces News asked chemical weapons expert Hamish de Bretton-Gordon to tell us more about the nerve agent and its effects on humans.
What is it?
Novichok is a sophisticated nerve agent (nerve agents are a type of chemical weapon first developed by Nazi Germany) which comes from organic phosphates and pesticides.
Exposure is most likely through inhalation or ingestion, although the agent can also be absorbed through the skin.
"Novichok is the very latest nerve agent, only developed and produced by the Russians,” said Mr de Bretton-Gordon.
"It was designed to counter NATO's capabilities, particularly NATO’s ability to detect it.
"It's very, very persistent and a tiny amount is enough to kill.
"We think the Russian modus operandi was to use it in small amounts for assassinations - and we've seen several of those - but possibly in larger amounts on the battlefield.
"It is possibly the most toxic man-made chemical ever produced."
What are its effects on humans?
Novichok is a nerve agent and, as the name suggests, it attacks the nerves in the human body.
"It is a common esterase inhibitor, and what that means is it prevents a chemical enzyme called acetylcholine from breaking down and when that happens your nerves get blocked," Mr de Bretton-Gordon continues.
This quickly leads to a number of problems that can ultimately prove to be deadly.
"Your nerves control all your muscles and all the major parts [and] organs in your body like the heart and the lungs and they make them flex uncontrollably and ultimately they destroy them.
"Without your nerves, you can't live - you stop breathing very quickly, your heart stops very quickly and generally death is pretty soon."
Is there a cure?
With Novichok designed to be fast-acting and more toxic than other chemical weapons, you might think the chances of effective treatment were very low, but treatment does exist.
"There is an antidote for Novichok and all nerve agents," says Mr de Bretton-Gordon.
"Every soldier, certainly in the British military, carries atropine when on operations and this reverses the effect of nerve agents and reverses the damage done to nerves."
However, Mr de Bretton-Gordon stressed that time remains an important factor in the effectiveness of the treatment.
"It's important that [treatment is] done in a timely fashion and generally you only inject yourself or a compatriot who is injured with up to three of these autojets.
"It is very, very effective and in a timely fashion it can save someone's life who has been poisoned by a nerve agent."
Cover image: The clean-up taking place in Salisbury following a nerve agent attack in the city.