The police officer who was left seriously ill after assisting poisoned ex-Russian spy Sergei Skripal has been named as Sergeant Nick Bailey.

Mr Bailey was among the first people to come to the aid of Mr Skripal and his daughter Yulia, after they were attacked with a nerve agent on Sunday.

The officer remains seriously ill in intensive care as a result of coming into contact with the nerve agent, though he is apparently "awake and talking".

Mr Skripal, 66, and his 33-year-old daughter are both fighting for their lives.

Counter-terror police are leading the investigation, which is being treated as attempted murder.

Police officers at the scene immediately after the attack on Mr Skripal and his daughter.

Kier Pritchard, chief constable for Wiltshire Police, said he had visited Mr Bailey and his wife in hospital but it was not yet clear what path his recovery would take.

“He’s well, he’s sat up, he’s not the Nick that I know, but of course he’s receiving a high level of treatment," he said.

I’m very confident he he’s getting the best professional support that he can but of course, he’s very anxious, he’s very concerned.”

Asked whether Mr Bailey would make a full recovery, he replied: “We are going to have to wait to see on that. It was great to see he was sitting up. I very much hope that Nick will be on his feet back at work very soon.”

The police chief praised Mr Bailey as "a great character, a huge presence in Wiltshire police, a well-liked, well-loved, massively dedicated officer."

"He did his very best on that night, " he added, all saying those who had responded had acted on "limited information" to protect the public.

"I'm massively proud of what Nick did, and all of my staff on that night. They did a first-class job."

Home Secretary Amber Rudd yesterday told Good Morning Britain she was "optimistic" for the Mr Bailey but said "it's too early to say" more.

She added: "The policeman is still seriously unwell but he is actually engaging, awake and talking to people."

Police in hazard suits working at the scene of the attack. Credit: PA

Ms Rudd said tests had confirmed that a "very rare" nerve agent had been used in the incident, though she refused to give more details.

Ministers have held an emergency meting over the case, amid concerns the attack could have been directed by state agents in Russia.

Mr Skripal, 66, is a former Russian double agent who is believed to have worked for MI6.

He was arrested in Moscow in 2004, but was later released and allowed to travel to the UK under a spy swap agreement.

Sergei Skripal and his daughter are critically ill.

Russia has firmly denied that it is behind the poisoning.

The case echoes the murder of another Russian ex-spy, Alexander Litvinenko, who died in the UK 12 years ago after being exposed to polonium.

A judge-led inquiry later concluded Mr Litvinenko's murder was state-sponsored and Russian President Vladimir Putin probably personally endorsed the attack.

Theresa May has said she will do do "what is appropriate" if evidence proves that Russia was behind the attack on Mr Skripal.

But she cautioned against jumping to conclusions, saying the police must be given the "space and time to conduct their investigation".