The victims of the nerve agent emergency in Wiltshire were not directly targeted, the security minister has said.
Ben Wallace disclosed that the “working assumption” is that the pair were exposed to Novichok either as a result of the attack on former Russian spy Sergei Skripal and his daughter Yulia in Salisbury earlier this year, or “something else”.
Referring to the Salisbury incident, Mr Wallace told BBC Radio 4’s Today programme: “I think what we said at the time was that this was a brazen and reckless attack in the heart of a very peaceful part of the United Kingdom, and that is part of the anger I feel about the Russian state is that they chose to use clearly a very, very toxic, highly dangerous weapon.”
One theory understood to be under investigation is that the pair may have inadvertently found a container – such as a phial or syringe – used to transport the nerve agent for the initial attack and discarded in a public place.
Novichok remains highly toxic for a considerable period of time, so even the tiniest trace remaining in a container picked up by the victims could account for their severe illness.
Areas in Salisbury known to have been visited by the Skripals were subject to decontamination, and it is not thought that the current incident has any link to those locations.
Prime Minister Theresa May sent a message to say that the Salisbury area remains “open for business” and the Government will provide whatever help is needed.
“All of my thoughts are with the victims and the people of Amesbury and Salisbury,” said Mrs May.
“After the brazen and reckless attempt to murder the Skripals with Novichok in March, the community showed tremendous fortitude, patience and resilience.
“Once again the public is having to contend with the consequences of two people being exposed to a nerve agent and I would like to personally thank local businesses and residents for their co-operation.
“We once again sincerely thank the brave emergency services for their response.
“The message from Salisbury is clear – it is very much open for business. The Government will continue to provide every support to the local community.”
The UK has reported the incident to the Organisation for the Prohibition of Chemical Weapons (OPCW), which previously visited Salisbury to obtain samples of the substance used to target the Skripals.
At the UK’s request, the OPCW was last month given new powers to name those who it regards as responsible for uses of chemical weapons.
The Kremlin described the Amesbury poisoning as “disturbing” and said Russia wished the victims a speedy recovery.
But Kremlin spokesman Dmitry Peskov told reporters in Moscow that Russia had so far received no “appeal” from the UK in relation to the incident.
According to the Tass news agency, Mr Peskov said: “This is very disturbing news. Of course, it triggers profound concern in connection with the similar incidents in the UK.
“We wish them a speedy recovery.”
– It was understood investigators are working on a theory that the pair came into contact with the deadly substance in a part of Salisbury city centre that was outside the clean-up launched after the attack against the Skripals.
– There were warnings that the new Novichok poisoning will raise “serious questions” over the massive clean-up operation launched following the March incident.
– The man and woman remained critically ill in hospital.
– Public Health England (PHE) said it did not believe there to be a “significant health risk” to the wider public, although its advice was being reviewed.
– Home Secretary Sajid Javid was preparing to chair a meeting of the Cobra emergency committee on Thursday.
Officers were called to a home in Muggleton Road, Amesbury, on Saturday morning when the 44-year-old woman collapsed.
They were called back later that day when the man, 45, also fell ill.
It was initially believed that the two patients fell ill after possibly using drugs from a contaminated batch, police have said.
But after further tests, authorities declared a major incident and on Wednesday night counter-terror police assumed responsibility for the investigation after the Government’s Porton Down laboratory concluded that the pair had been exposed to Novichok.
A senior Government source told the Press Association it is believed there was cross-contamination of the same batch of nerve agent involved in the “reckless” Salisbury attack, as opposed to a secondary attack.
“They (the authorities) have never been able to ascertain the item used to deposit the Novichok and it’s possible the pair have come into contact with that item,” the source said.
Metropolitan Police Assistant Commissioner Neil Basu, the country’s most senior anti-terror officer, acknowledged there will be “a great deal of speculation” over potential links between the two incidents.
“I must say that we are not in a position to say whether the nerve agent was from the same batch that the Skripals were exposed to.
“The possibility that these two investigations might be linked is clearly a line of inquiry for us.”
Health officials say their current advice, based on the small number of casualties affected, is that the risk to the public is low.
Professor Paul Cosford, medical director of Public Health England, told the Today programme: “The sites that were the subject of the clean-up after Skripal are not associated with this incident.
“So there should not be any concern that the clean-up after the previous incident has not worked here.”
According to friend Sam Hobson, he visited the park with the couple on Friday evening.
He told The Guardian that, after Ms Sturgess was taken to hospital on Saturday morning, he accompanied Mr Rowley to a Boots chemist in Amesbury before the pair attended a free hog roast at a local baptist church.
Neighbours living near the scene were keen to find out more about what had happened to the couple.
College student Chloe Edwards, 17, described seeing police cars, fire engines and people in “green suits” on Saturday night.
“We were just eating our dinner and all these emergency vehicles turned up,” she said.
“They were putting on these green suits and we thought it was the gas as our electricity was turned off as well.”
She said the vehicles arrived at about 7pm and she and her family were told to stay inside their home until about 10pm.
“We wanted to know what happened and, with the Russian attack happening not long ago … we just assumed the worst,” she said.
The episode in Salisbury – the first use of a nerve agent in Europe since the Second World War – sparked international outrage.
The Kremlin has repeatedly denied being behind the attack.
Mr Skripal and his daughter Yulia have since left hospital.