Picture Credit: Press Association
Foreign Secretary Boris Johnson has promised that Britain will respond "robustly" if evidence emerges of state responsibility after a former Russian double agent was left critically ill following suspected exposure to an unknown substance.
A pizza restaurant in Salisbury was closed by police late on Monday night as Sergei Skripal, 66, fought for his life in hospital a day after he was found unconscious in the Wiltshire city along with his 33-year-old daughter Yulia.
According to the BBC, Skripal gave lectures at military establishments and to intelligence services and was available as an expert on how the GRU operated (the Russian military intelligence agency).
The Salisbury area is well-located for its proximity to military establishments, where he was reportedly giving talks from time to time.
Mr Johnson was answering an urgent question in the Commons when he said he wanted to address speculation about the "disturbing" incident.
The Foreign Secretary noted that the case has "echoes" of the death of Alexander Litvinenko - a Russian dissident who died after being poisoned in London in 2006.
He told MPs:
"While it would be wrong to prejudge the investigation, I can reassure the House that should evidence emerge that implies state responsibility, then Her Majesty's Government will respond appropriately and robustly."
Mr Johnson said Russia is now "in many respects a malign and disruptive force and the UK is in the lead across the world in trying to counteract that activity".
He added that the Government may be forced into looking again at sanctions if suspicions prove to be well-founded.
Russia said it is willing to co-operate but had no information regarding the "tragic situation”.
Skripal was convicted in 2006 of passing state secrets to MI6 before being given refuge in the UK as part of a spy swap.
The former colonel in the Russian military intelligence, who was sentenced to 13 years in prison, was among four convicts who were given pardons and one of two sent to Britain in 2010 in a deal that was said at the time to be the largest exchange since the Cold War.
Former Scotland Yard counter-terror chief Richard Walton said: "The investigation must take its course but if this is state-sponsored terrorism, and it looks entirely possible, then it will have grave consequences for UK-Russia bilateral relations.
"Relations that are already at breaking point. The UK cannot and will not tolerate state-sponsored terrorism of any kind."
The Castle Street branch of the chain restaurant Zizzi was "secured as a precaution", the force said, adding Public Health England believed there was no risk to the public.
Officers in regular uniforms and plainclothes spoke to staff inside and worked in tents in the area the pair were found.
A CCTV image of a man and woman walking between the Zizzi restaurant and the bench near a shopping centre where Mr Skripal was found is believed to be of interest to police.
A picture of the two - taken at 3.47pm on Sunday - was taken by officers from a camera at Snap Fitness 24/7, the gym manager told the Press Association.
Freya Church, 27, spotted the pair "slumped" and "passed out", said the couple on the CCTV picture was "100%" the people she saw on Sunday.
The gym worker, from Salisbury, said: "She was leaning on him, slumped. She looked passed out and he was looking up, doing these hand movements.
“His eyes were glazed. To be honest, I thought they were just homeless."
Freya Church told the BBC they "looked so out of it".
She said: "He was doing some strange hand movements, looking up to the sky.
"It looked like they had been taking something quite strong."
Temporary Assistant Chief Constable Craig Holden said: "The pair… were taken to Salisbury District Hospital.
"This has not been declared as a counter-terrorism incident and we would urge people not to speculate."
"However, I must emphasise that we retain an open mind and we will continue to review this position."
Bill Browder, an anti-corruption campaigner, said: "We don't know much, but based on the headlines from yesterday, who the person was, his relationship with the Kremlin, and the circumstances of his collapse, the first operating assumption should be that this was an assassination attempt by the Kremlin against a traitor of Russia."
Garry Kasparov, a former world chess champion and critic of Vladimir Putin, was among those who drew comparisons with the death of Russian dissident Alexander Litvinenko in 2006.
But Igor Sutyagin, who was part of the same swap deal as Skripal and is now a research fellow at RUSI, urged caution.
He told the Associated Press: "There are lots of former security officers that deserted to the West. It is necessary to balance this information."
Salisbury District Hospital declared a major incident but told patients to attend appointments as normal unless advised otherwise.
A spokesman for Public Health England (PHE) said anyone exposed to the unknown substance had been decontaminated "as is standard practice in situations like this".