The Daily Star's FREE newsletter is spectacular! Sign up today for the best stories straight to your inbox Sign up today! Thank you for subscribing See our privacy notice Invalid Email

The man and a woman, both in their 40s, are in a critical condition in Salisbury District Hospital, Wiltshire Police said.

A number of places in Amesbury and Salisbury have been cordoned off as a precaution.

Counter terror police have now been called in to lead the probe – and samples have been sent to Porton Down research lab.

Public Health England (PHE) said it did not believe there to be a "significant health risk" to the wider public, although its advice was being reviewed.

Images from the scene showed a police presence in Muggleton Road, Amesbury, where the pair were found unconscious inside a property on Saturday, while a nearby Baptist church appeared to have been cordoned off.

(Image: SWNS)

The address is thought to be on a new housing development on the southern edge of the town, which lies close to Stonehenge.

Police and emergency services initially believed the pair may have taken illegal drugs, however further tests are now being carried out.

The incident comes after former Russian spy Sergei Skripal and his daughter, Yulia, were left poisoned by a suspected military nerve agent in Salisbury, which is around eight miles from Amesbury, in March.

Crime scene investigators were present at a cordoned-off park in nearby Salisbury.

Police were unable to confirmed this was linked to the Amesbury incident, but neighbours of Queen Elizabeth Gardens said the cordon appeared in the early hours of Wednesday.

Officers surrounded the entire green with police tape, including a children's play park and public toilets.

A police statement on Tuesday said: "Wiltshire Police and partners have this evening declared a major incident after it is suspected that two people might have been exposed to an unknown substance in Amesbury.

"Emergency services were called to an address in Muggleton Road, Amesbury, on Saturday evening (June 30) after a man and woman, both in their 40s, were found unconscious in a property.

"They are both currently receiving treatment for suspected exposure to an unknown substance at Salisbury District Hospital. They are both in a critical condition.

"It was initially believed that the two patients fell ill after using possibly heroin or crack cocaine from a contaminated batch of drugs.

"However, further testing is now ongoing to establish the substance which led to these patients becoming ill and we are keeping an open mind as to the circumstances surrounding this incident."

(Image: SWNS)

A number of scenes believed to be areas they frequented before they fell ill were cordoned off overnight.

Meanwhile, there was an increased police presence in and around Amesbury and Salisbury.

Salisbury District Hospital was "open as usual" and officials advised people to attend routine appointments unless they are contacted to do otherwise.

A PHE spokesman said: "The current advice from PHE England, based upon the number of casualties affected, is that it is not believed that there is a significant health risk to the wider public. This will be continually assessed as further information becomes known".

Mr Skripal, 67, and his 33-year-old daughter were left in a critical condition after they were found slumped on a bench in Salisbury city centre on March 4.

It is believed one of the last places the couple were seen in public was a family fun day at Amesbury Baptist Church on Saturday afternoon.

Roy Collins, church secretary, said: "Last weekend we held a community fundraiser and we understand this may well be the last event this couple went to in public."

He said he woke to find the church cordoned off by police at 6am on Wednesday.

"We are all quite puzzled and shocked - naturally the connection with Salisbury and recent events there mean there is a heightened public interest," he added.

"We are praying for the couple, one of our members knows them and clearly there are concerns for them and any others in the community.

"They are not church members or regulars."

(Image: SWNS)

Mr Collins said around 200 people attended the community event, including many families and children, but "nobody else has suffered any ill-effects".

"There have been no reports of any other incidents," he added.

"It was a beautiful, sunny day and it was a glorious event, there was nothing going on that was nefarious.

"This is a real surprise and shock to us - we do continue to keep the couple in our prayers."

Mayor of Amesbury councillor Margaret Strange said she was in the dark about what happened.

"I know as much as anybody else," she said after speaking to officers on duty outside the address in Muggleton Road.