A woman exposed to nerve agent Novichok in Amesbury has died, police have confirmed, as a murder investigation has been launched. 

Dawn Sturgess, a mother of three, died on Sunday evening the Met said in a statement shortly before 10pm.  

Her family has been informed and is receiving support from specially trained family liaison officers, the Met said, adding that a post-mortem is scheduled to take place in “due course”. 

The 44-year-old was found unconscious at a residential address along with her partner, Charlie Rowley, on June 30. 

Rowley, 45, remains critically ill in hospital.

Assistant Commissioner Neil Basu, the head of UK Counter Terrorism policing said: “This is shocking and tragic news. Dawn leaves behind her family, including three children, and our thoughts and prayers are with them at this extremely difficult time.”

He added: “This terrible news has only served to strengthen our resolve to identify and bring to justice the person or persons responsible for what I can only describe as an outrageous, reckless and barbaric act. 

“Detectives will continue with their painstaking and meticulous work to gather all the available evidence so that we can understand how two citizens came to be exposed with such a deadly substance that tragically cost Dawn her life.”

Basu said the Met’s thoughts were also with Rowley’s family as he fights for his life. 

Responding to the news, Prime Minister Theresa May said: “I am appalled and shocked by the death of Dawn Sturgess, and my thoughts and condolences go to her family and loved ones. Police and security officials are working urgently to establish the facts of this incident, which is now being investigated as a murder.”

She added: “The Government is committed to providing full support to the local community as it deals with this tragedy.”

Salisbury MP John Glen wrote on Twitter: “Deeply saddened to hear that Dawn Sturgess has died at Salisbury District Hospital.

“I can assure the people of South Wiltshire that the police will be given all necessary resources to find out exactly what has transpired and bring those responsible to justice.”

Angus Macpherson, Police and Crime Commissioner for Wiltshire and Swindon, also expressed his sympathy for Sturgess’ family at “this terribly sad and difficult time”.

“I send my condolences to them as they attempt to come to terms with what has happened over the last number of days,” he said.

“Ms Sturgess was an innocent member of the public who should have been able to go about her daily life without becoming an unwilling victim in such an unprecedented, international, incident.  

 “I am horrified and appalled that an illegal and lethal nerve agent has used on the streets of our county. And while the city of Salisbury has bounced back so resiliently, it saddens me greatly that Ms Sturgess, and now her family, are bearing the devastating impact of this incident.”

The Met said the murder inquiry is being led by the Counter Terrorism Policing Network and around 100 detectives are working “round the clock” alongside colleagues from Wiltshire police.

The Defence Science and Technology Laboratory at Porton Down confirmed on Wednesday that Sturgess and Rowley had been exposed to Novichok.

“No-one else has presented with the same symptoms linked to this incident,” the Met said. 

“Further tests of samples from Dawn and the man showed that they were exposed to the nerve agent after touching a contaminated item with their hands.

“Detectives are working as quickly and as diligently as possible to identify the source of the contamination, but this has not been established at this time.”

The Met said there was no evidence that they visited any of the sites that were 
decontaminated following the attempted murders of former Russian spy Sergei Skripal and his daughter, Yulia, in Salisbury on 4 March.

“We are not in a position to say whether the nerve agent was from the same batch that the Skripals were exposed to,” the Met said, adding that the investigation into the attempted murders of the Skripals were ongoing.

“The possibility that the two investigations might be linked is clearly a key line of inquiry for police. However, it is important that the investigation is led by the evidence available and the facts alone,” the Met said. 

Macpherson said that while there was a “sense of anxiety” over the poisonings the risk to the public “remains low”.

Sturgess and Rowley were taken to hospital on June 30 after falling ill at a residential address. Sturgess was taken to hospital around 10.15am and Rowley several hours later, around 3.30pm. 

The Met urged anyone who may have information that could assist with this investigation and would urge anyone to help to contact police by calling 0800 789 321.