What triggered concern over the incident in Amesbury, Wiltshire?

A couple living in Amesbury, Dawn Sturgess and Charlie Rowley, were taken to hospital on Saturday night. The initial suspicion, according to police, was that it was drugs-related, but doctors were unable to identify the substance.

The same hospital treated Sergei and Julia Skripal, the Russian couple targeted in Salisbury by the nerve agent novichok, and it was worried by similarities.



Overnight on Tuesday, Wiltshire police, sensitive after the Salisbury attack, declared it a “major incident”.



The police and government throughout Wednesday had said they were keeping an open mind: it might be something “sinister” connected to the Skripal attack or there might be a totally different explanation. They said they were awaiting the outcome of tests into the mystery substance.



By late Wednesday evening, the police announced the tests showed it was novichok, a type of nerve agent originally developed in Russia. It was used in the attack on the Skripals, smeared on a door handle.

Hamish de Bretton-Gordon, former commanding officer of the UK Chemical, Biological, Radiological and Nuclear Regiment, said the key was Amesbury’s proximity to Salisbury.



“If it had happened anywhere else, it is doubtful if anyone would have paid much attention,” he said. “The authorities are concerned it could be collateral damage from Salisbury.”

Why did the Wiltshire police statement in the early hours of Wednesday morning throw Whitehall and Westminster into panic?

The statement came as a surprise on Wednesday morning. It was issued overnight and the first many officials knew about it was when they got up in the morning.

The police statement described it as a “major incident”. The government convened a meeting of its Cobra emergency committee, which is usually made up of intelligence officials, ministers and police.

Why were the tests being carried out at the secretive biological warfare centre Porton Down?

Normally, such tests would be carried out in-house at the hospital or another NHS agency. But Porton Down is close by and identified the use of novichok in the Skripal case. That experience made it easier and faster for them to establish that the substance was novichok.



What happens now?

The first priority for the police will be to establish how and where the couple came into contact with the novichok and why it has only surfaced now months after the Skripal attack.

The police have been working to decontaminate Salisbury and public health authorities had issued reassurances that there was no danger to the public.

Another priority is to establish whether the novichok was from the batch as was used in the Skripal case.



What will be the diplomatic fall-out?

The UK government and the intelligence agencies have already blamed the Russian government for being behind the Skripal attack and described the first use of a nerve agent on European soil since the second world war as irresponsible.



The government can point to the the latest casualties as further evidence of recklessness.

The latest twist comes at time when Russia’s image has been burnished by a successful staging of the World Cup. More significantly though, it comes less than a week before a Nato summit in Brussels to discuss how the transatlantic alliance should deal with Russia and ahead of Donald Trump’s meeting with Vladimir Putin. Will Trump even raise it?