Properties to be searched in bid to trace source of Novichok poisoning

Forensic investigators searching for the deadly Novichok-tainted item that left a couple fighting for their lives are expected to begin combing through key sites in Wiltshire.

Three incident response vehicles and two fire engines joined police on Friday morning at the Amesbury flat of Charlie Rowley, who remains critically ill after coming into contact with the same nerve agent used in an attack in nearby Salisbury four months earlier.

Police have been unable to locate the source of the contamination and have not ruled out more people falling ill from coming into contact with the substance left over from the attempted murder of Sergei and Yulia Skripal.

Dawn Sturgess, 44, and Mr Rowley, 45, were taken ill on Saturday at his home, around eight miles (13km) from where the former Russian spy and his daughter were poisoned by Novichok in Salisbury in March.

Forensic tents are positioned outside John Baker House in Salisbury, the supported housing where mother-of-three Ms Sturgess lived, which has been evacuated.

Wiltshire residents have been told to expect investigators in hazardous material suits to descend on the scenes, while other sites the couple were known to have visited before being taken ill are behind cordons.

One theory understood to be being investigated is whether the pair inadvertently found the container used to transport the nerve agent in the Skripal attack before being recklessly discarded.

Mr Rowley has been described as having foraged for goods to fix and sell and is known to have collected discarded cigarettes.

The second nerve agent emergency in four months prompted a diplomatic row, with Home Secretary Sajid Javid accusing the Russian state of using Britain as a "dumping ground for poison".

The Russian Embassy hit back, accusing the Government of trying to "muddy the waters" and "frighten its own citizens".

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

"Following further tests of samples from the patients, we now know that they were exposed to the nerve agent after handling a contaminated item," the Metropolitan Police said.

"Detectives are working as quickly and as diligently as possible to identify the source of the contamination.

"Meticulous and systematic searches are under way at a number of sites."

The Chief Constable of Wiltshire Police defended his force's initial response to the latest poisoning but could not rule out that further people could fall ill.

Kier Pritchard also said he "fully supports" the decisions taken by officers who initially thought the couple had collapsed after taking illegal drugs.

During a meeting on Thursday, he said: "I hope we are not back in this position in four months' time."

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.

As the fall-out continued:

- Shadow home secretary Diane Abbott warned that British streets must not be allowed to become "killing fields for state actors".

- Prime Minister Theresa May declared Salisbury is "very much open for business" after residents raised fears that the new case will hamper the local economy.

- Six sites visited by Mr Rowley and Ms Sturgess before they fell ill were cordoned off.

- The UK reported the incident to the Organisation for the Prohibition of Chemical Weapons.

Earlier on Thursday, security minister Ben Wallace said the latest victims were not directly targeted.

The episode in Salisbury - the first use of a nerve agent in Europe since the Second World War - sparked international outrage.

Mr Skripal and his daughter have since left hospital.