The public health chief charged with containing the Salisbury Novichok attack has recalled her “total disbelief” after the deadly nerve agent resurfaced several miles away months after the original poisonings.

Tracy Daszkiewicz said the death of Dawn Sturgess, who unwittingly sprayed herself with the lethal chemical disguised inside a perfume bottle, “absolutely floored” her and was “the most awful part” of the whole saga.

Mrs Daszkiewicz had been Wiltshire Council’s public health director for only several months when Russian former double agent Sergei Skripal 66, and his 33-year-old daughter Yulia were found slumped on a park bench foaming at the mouth on March 4 2018.

The mother-of-four, 47, told PA “as induction programmes go, it was fairly unique”.

She said: “At the time I don’t think anything could’ve been done differently. It was such a one-off extraordinary event.

“For me, professionally you learn so much and you’re sort of glad you were involved, but always wish it had never happened.

“It’s a huge contradiction. Particularly when a life was lost and the extended trauma that people involved have experienced.

“I don’t know whether I look back and think ‘I wish that had been done differently or I wish I’d made a different decision’ but I have taken an awful lot of learning and experience from it.

“Nobody had dealt with anything like this.”

Mrs Daszkiewicz, who was portrayed by Anne-Marie Duff in a BBC drama called The Salisbury Poisonings, said when news came through that Ms Sturgess, 44, was critically ill with Novichok poisoning in late June she was in “total disbelief”.

The public health expert had met Ms Sturgess, of Amesbury, several miles north of Salisbury, at a community event around four years previously and said she recognised her from a picture.

She said: “The most awful part of all of it was when we knew how poorly Dawn was. Losing Dawn was absolutely devastating.

“I remember getting the phone call and us regrouping … I can’t even describe it, just absolute disbelief, total disbelief, and that whole realisation that you’re almost starting again.

“Major incidents are usually denoted by mass casualties, mass impact and, in worst-case scenarios, mass fatalities. This incident did teach me that one is too high a number.

“Everybody’s name matters, the fact we’ve only got one name, that name is as important as any other.

“Of course it could have been higher numbers but one is too many for me.”

Mrs Daszkiewicz, now working in population health and wellbeing at Public Health England, added that, three years on from the incident, some Salisbury residents, particularly those living behind cordons for months and whose livelihoods suffered, are only now coming to terms with the gravity of the event.

She said: “Coming out of major incidents there’s a lot of emphasis on getting services and buildings back to where they were but the personal impacts take longer.

“There’s a recovery curve that happens on the personal level. You can often be two to five years post incident before people start to really reflect and feel the impacts and the trauma of what they’ve been through.

“The impacts of it are significant and are still being felt today, that hasn’t gone away for a lot of people.”