A number of police officers were taken to hospital with ‘minor symptoms’ after responding to the emergency call about the unconscious people on a bench in Salisbury on Sunday.
Since, the nation’s media have named the pair found in The Maltings as former Russian spy Sergei Skripal, 66, and his daughter Yulia Skripal, in her 30s.
Emergency services, including Wiltshire Air Ambulance, were called The Maltings at around 4.15pm on 4 March, after concerns were raised for the welfare of a man and a woman.
Their admission to hospital led to a major incident which has seen A&E closed on Monday morning, with specialist ambulance crews and firefighters working to decontaminating the area.
They are currently being treated for suspected exposure to an unknown substance, and both remain in a critical condition in intensive care.
Counter-terrorism police are understood to be involved in the investigation into the suspected poisoning of a former Russian spy, according to reports.
A spokesperson for Wiltshire Police said: “As part of our enquiries, a number of scenes have been secured. These include the Zizzi restaurant on Castle Street and The Bishop’s Mill pub in The Maltings.
“At this time, we cannot confirm how long these cordons will remain in place.”
The advice from Public Health England remains that, based on the evidence to date, currently there doesn’t appear to be any immediate risk to public health.
“We can confirm that a small number of emergency services personnel were assessed immediately after the incident and all but one have been released from hospital”, the spokesperson added.
“The public are likely to continue to see an increased police and emergency services presence in the city centre today to provide reassurance.
“We continue to work with a range of partner agencies, including Counter Terrorism Policing, Public Health England and Salisbury District Hospital.
“We have access to a wide range of specialist resources and services that are helping us to understand what we are or aren’t dealing with at this time.
“We would continue to appeal to any members of the public who may have information in relation to this incident to contact us immediately via 101 or 999. We would like to reassure members of the public that incidents of this nature are taken extremely seriously.
“We would like to take this opportunity to thank members of the public who have assisted us so far and respected the cordons which remain in place.”