Military Research Site Testing Unknown Wiltshire Substance

A police cordon near to Amesbury. (Picture: PA).

Tests are being carried out at a military research facility at Porton Down after a couple were left in a critical condition after being exposed to a mystery substance.

A Defence Science and Technology Laboratory (DSTL) spokesperson confirmed to Forces News they are supporting the police investigation.

Counter-terrorism police in Amesbury in Wiltshire are working with officers in the area after the pair were found unconscious over the weekend.

Police have declared a major incident.

Amesbury is around eight miles from where former Russian spy Sergei Skripal and his daughter Yulia were poisoned with a nerve agent in March, but it is not thought that the individuals are linked in any way to Russia or to the Skripals.

Military personnel were deployed in the aftermath of that incident to assist with the cleanup operation.

The Metropolitan Police, who lead the national counter-terrorism network, said in a statement: "Given the recent events in Salisbury, officers from the counter-terrorism network are working jointly with colleagues from Wiltshire Police regarding the incident in Amesbury.

"As Wiltshire Police have stated, they are keeping an open mind as to the circumstances surrounding the incident and will update the public as soon and as regularly as possible."

The man and woman from Amesbury are in a critical condition in Salisbury District Hospital.