Spy scandal: PM promises action after poisoning inquiry widens to 21 people

"The public should not be alarmed and the public health advice remains the same", a police statement said. "The military has the expertise and capability to respond to a range of contingencies".

Some of the 180 military personnel who have been sent to help the investigation are specialists in chemical biological radiological and nuclear (CBRN) warfare.

Those deployed include instructors from the Defence Chemical Biological Radiological and Nuclear Centre and the 29 Explosive Ordnance Group, who are experts in bomb disposal.

UK Home Secretary Amber Rudd visited the city on Friday, including the area around the bench - now covered by a police forensics tent - where Mr Skripal and his daughter were found.

On Thursday night, an eyewitness said police had been searching a auto at a vehicle recovery centre close to the Russian victim's home earlier that day.

What makes this particular attack so sinister, and why speculation about who is responsible has gripped the nation, is that nerve agents are incredibly hard to come by, and are ordinarily developed by States.

However, Lavrov stated that if British authorities were interested in cooperating with Russian Federation in relation to any case, "be it poisoning of British subjects, be it rumors of interfering in U.S. campaign, if help is really needed, we are ready to look at such possibility". "This is a awful incident and my thoughts remain with the victims and their families". A police officer who helped investigate is in serious condition, and a total of 21 people have received medical treatment.

Skripal, 66, a former colonel in the Russian military intelligence, and his 33-year-old daughter, Yulia, were found unconscious in Salisbury on Sunday.

"I want to remind people that Litvinenko's death was also attributed to Russian Federation, but hasn't been investigated, because court proceedings, which were called 'public, ' were in fact closed".

She added police needed to be given space "to do their investigation".

"We are also receiving support from other police forces through the National Police Coordination Centre and I sincerely thank all officers, staff and volunteers for their continued professionalism and hard work in what is a very difficult, fast paced and complex situation".

This attack was not just an attack on a former Russian spy, but also put at risk both the public and our courageous emergency-service workers.

Prime Minister Theresa May said her thoughts were with all the victims, and praised the response of the emergency services.

Investigators said they had identified the specific agent, but were not disclosing that information.

The graves of Mr Skripal's wife and son at a Salisbury cemetery have also been taped off.

The cause of 59-year-old Ms Skripal's death was recorded as endometrial cancer and Alexander, 44, was said to have suffered liver failure while on holiday.

The dispute regarding the allegiance of Skirpal has raised the concerns that the spy might be working for both the Russian and British intelligence services as a double agent.

The use of a nerve agent - with its last known use in a targeted attack against the Kim Jong-nam, the estranged brother of North Korea's leader - and Mr Skripal's past have suggested that the Russian state was involved in the attack.

  • Jon Douglas