A consultant who treated poisoned Russian ex-spy Sergei Skripal and his daughter Yulia has revealed he did not think the pair would survive.
Another doctor at Salisbury District Hospital said speaking to other staff about the attempted assassination of the pair using a nerve agent was like nothing he could have envisaged in his "wildest imagination".
Medics at the hospital told BBC Newsnight about the extraordinary situation they faced when the Skripals were rushed into their care after being found unconscious from the effects of the military nerve agent Novichok on March 4.
Dr Stephen Jukes, intensive care consultant, said: "When we first were aware this was a nerve agent we were expecting them not to survive. We would try all our therapies. We would ensure the best clinical care. But all the evidence was there that they would not survive."
Lorna Wilkinson, director of nursing, said she had wondered how big the situation would get when policeman Nick Bailey became the third person admitted in connection with the poisoning. She said she began thinking: "Have we just gone from having two index patients having something that actually could become all-consuming and involve many casualties? Because we really didn't know at that point."
Hospital medical director Dr Christine Blanshard told Newsnight the long-term prognosis for the trio was unknown.
Moscow has repeatedly denied responsibility for the attack.
BBC Newsnight is on BBC Two tonight at 10.30pm