Amesbury in Wiltshire has again been the centre of a chemical weapons incident after two Brits were poisoned with nerve agent Novichok
The pair were rushed to hospital with similar symptoms to Russian spy Sergei Skripal, 66, and his daughter Yulia, who were targeted by the poison in March
It is thought the latest victims may have accidentally stumbled upon the Novichok in a bag in a park
Theresa May publicly pointed the figure of blame at Russia for launching a chemical attack on British soil
In a statement in the House of Commons, the PM said that it was "highly likely" Russia was behind the assassination attempt of using the deadliest nerve agent ever created
The initial attack is believed to be the first time a chemical weapon has been used on the streets of Britain
What is Novichok? This group of nerve agents was developed by the Soviet Union in the 1970s and 80s and is said to be up to ten times stronger than VX, a nerve agent created by the UK in the 1950s
VX has long been the most widely available deadly nerve agent used in state sponsored killings - being used by Saddam Hussein and Kim Jong-Un to kill opponents
But Novichoks - meaning 'newcomer' in Russian - were designed as "binary weapons", meaning they are comprises of two relatively harmless ingredients that only become deadly when mixed together
This makes them easier to transport, handle and gives them a much longer shelf life than other nerve agents
Colonel Hamish de Bretton-Gordon, the former head of Britain’s Chemical, Biological Radiation and Nuclear regiment told the Express: "It is designed to be undetectable for any standard chemical security testing
"Skripal would only have needed to touch it, as he opened a parcel, for it to be absorbed into his bloodstream
" Read More Novichok poisoning Why use Novihok and not another nerve agent? It was designed to be undetectable and bend international rules on the control of chemical weapons These agents were designed to achieve four objectives: To be undetectable using standard equipment used by the UK and its allies; To go through standard issue NATO chemical protective gear; To be safer for operatives in the field to handle; To circumvent the Chemical Weapons Convention list of controlled chemical weapons
Another advantage is how it can be used it can be dispersed as an ultra-fine powder instead of a gas/vapour
It is also relatively easy to get your hands on the ingredients, requiring just a few chemicals which are used in normal chemical and industrial settings
The method however is incredibly complex and took Russian scientists close to a decade to perfect
What does it do and how is it treated? Nerve agents work by interfering with the central nervous system, causing the body to become over stimulated
But unless you know which ingredients were used it is almost impossible to guess at the symptoms or design an effective treatment - making it more resistant to antidotes
All Novichok agents are more toxic than VX with some rumoured be up to 10 times more effective
But because of the uncertain ingredients they could render existing antidotes ineffective
It is believed that the agent attacks muscles especially those around the heart and lungs, leading to respiratory and cardiac arrest, and then death
How long does Novichok last? Novichok nerve agents were designed to be more toxic than others, like VX
Effects for some versions of the poison can take 30 second to two minutes to become apparent - by then it is often too late
Is this the first time it has been used as a weapon? It is generally agreed that Novichok was used on the street in Salisbury, and this would mark the first record of it has being used as a weapon
But it has long been controversial in the international community. Novichok became famous in the 90s, when a Soviet scientist called Vil Mirzayanov revealed that the country had secretly developed the powerful nerve gas – which was far more potent than anything in the US
Though the Soviet Union had been developing it for some time, it didn't become known for as much as a decade after it was actually available, because it had been kept entirely secret
It wasn't clear how much of it the Soviet Union actually developed, though Mr Mirzayanov said there was enough chemical weapons "to kill tens of millions"
Novichok was developed in much smaller amounts, he said, meaning there might only be enough to kill several hundreds of thousands of people