Investigators in hazmat suits enter Novichok victim's home

Forensic investigators in hazardous material suits and gas masks have begun searching the building where one of the latest Novichok victims lives.

Two people in camouflage protective clothing entered the John Baker House assisted-living accommodation in Salisbury, where mother-of-three Dawn Sturgess, lives after they took a sample from the outside of the building shortly after 3pm on Friday.

The building is a short distance away from many of the sites closed to the public after the attempted murder of a former Russian spy with the nerve agent in March.

Ms Sturgess, 44, and her partner, Charlie Rowley, 45, remain in a critical condition after being taken ill on Saturday after touching a contaminated item.

Those in camouflage were followed in by two others, one of whom was taking pictures, as they began combing for the deadly substance.

They took a swab from the exterior of the building on Rollestone Street, which is now under a heavy cordon and lined by forensic tents.

There was also a heavy operational presence at Mr Rowley's flat, where they were both taken ill.

Incident response vehicles and fire engines joined police at his Amesbury home.

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 after Sergei and Yulia Skripal were targeted.

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 under investigation 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 Government's Cobra emergency committee will meet on Friday afternoon to discuss the latest developments.

The meeting of officials will be chaired by the deputy national security adviser Madeleine Alessandri.

Wiltshire Chief Constable Kier Pritchard visited the Amesbury site on Friday.

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."

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.

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.