A teenage girl was the first person to help the novichok poisoning victims Sergei and Yulia Skripal, it has emerged.

Abigail McCourt was with her family when she saw the 66-year-old former KGB spy and his daughter collapsed on a bench at the Maltings shopping centre in Salisbury on the afternoon of 5 March last year.

The 16-year-old thought Sergei Skripal had suffered a heart attack and alerted her mother, Alison, who is an army colonel and chief nursing officer, and they went to administer first aid.

“It was my brother’s birthday and we were out celebrating, and we were coming home and I saw them on the bench,” Abigail, who learned first aid at school, told the Salisbury-based radio station Spire FM.

“At this point people were still walking past and I don’t think anyone had really noticed them. I told my mum because I thought he was having a heart attack. We went over and it developed from there.

“We went home and the next day I was talking to some of my friends about it, and at break someone Snapchatted me and said, ‘Is this the thing you were talking about?’, and I was ‘OK, wow’.

“I was a bit shocked, to be honest, because I don’t think I was expecting that to have happened. I needed to phone my mum and see if she was OK. It was a bit surreal.”

Abigail, who underwent hospital tests to see if she had been contaminated by the deadly nerve agent, was speaking after winning a Spire FM local hero award.

Abigail, who was nominated by her mother, said she put her first aid training to good use and believed she made a difference.

“It just all helped and I did make a massive difference, I think, because the woman wasn’t breathing at the time we found her,” said the teenager from Larkhill, Wiltshire.

“If someone is in trouble you have got to do something, and I don’t think you really question it at all.”

Alison McCourt told the radio station she was “immensely proud” of her daughter. “I just think she has been incredibly brave at the time to rush in. She’s trained in first aid and is in the cadet force at school, and she would never walk on by even if it was obvious it was dangerous,” she said.

“I know she’d do it all again if required to do so, which makes me immensely proud to be her mother.”

Investigators believe the Skripals first came into contact with the poison when it was sprayed on the door handle of the former spy’s home in Salisbury.

Skripal and his daughter survived the attack, which Theresa May said had almost certainly been approved by the Russian state.

Dawn Sturgess, 44, fell ill in Amesbury months after the incident and died in hospital in July after coming into contact with a perfume bottle believed to have been used in the attack on the Skripals and then discarded.

Her partner, Charlie Rowley, 45, was also exposed to the nerve agent but was treated and discharged.

Two Russian nationals have been accused of travelling to the UK to try to murder Sergei Skripal with novichok.

Evidence gathered by intelligence agencies led the government to conclude that the men were officers with Russia’s military intelligence service, the GRU.

The two suspects – known by their aliases Alexander Petrov and Ruslan Boshirov - were caught on CCTV in Salisbury the day before the attack.