Woman Dies After Exposure To Novichok Nerve Agent

The Amesbury woman died on Sunday evening, UK Police say.

A woman who was exposed to nerve agent Novichok has died UK police say.

Dawn Sturgess, 44, was taken to hospital in a critical condition following the poisoning, however died on Sunday. Her 45-year-old partner Charlie Rowley was poisoned at the same time and remains in hospital.

Police are continuing to investigate how Sturgess and Rowley, came across an item contaminated with Novichok, which was developed by the Soviet military during the Cold War.

The pair were just a few kilometres from where Russian ex-spy Sergei Skripal and his daughter were struck down by the same agent four months ago.

The March attack on the Skripals prompted the biggest Western expulsion of Russian diplomats since the Cold War as allies sided with Britain's view that Moscow was either responsible or had lost control of the nerve agent.

Moscow hit back by expelling Western diplomats.

The death of Sturgess was being investigated as a murder, police said in a statement on Sunday.

UK Prime Minister Theresa May said that authorities are doing everything they can to determine how Sturgess came to be poisoned.

"I am appalled and shocked by the death of Dawn Sturgess, and my thoughts and condolences go to her family and loved ones," May said.

"Police and security officials are working urgently to establish the facts of this incident, which is now being investigated as a murder."

Assistant Commissioner Neil Basu, the head of UK Counter Terrorism policing, said Sturgess' death was "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 said.

Theresa May left "appalled and shocked" after Sturgess' death. Image: Getty Images.

The two Britons were initially thought to have taken an overdose of heroin or crack cocaine.

But tests by the Porton Down military research centre showed they had been exposed to Novichok. Britain has notified the global chemical weapons watchdog, the Organisation for the Prohibition of Chemical Weapons (OPCW).

Britain's interior minister Sajid Javid said earlier on Sunday that police were still working to discover how the two individuals were exposed to the nerve agent.

They had a working hypothesis that the two poisoning incidents were connected, he said, although he added that there were no current plans for further sanctions against Russia.

The investigation is being led by detectives from Britain's Counter Terrorism Policing Network and around 100 detectives are working round the clock alongside colleagues from Wiltshire police.

With AAP.