The former headteacher of Dunblane Primary School has spoken about his “enormous guilt” 20 years after the massacre.
Ron Taylor said he felt he should have been able to protect the 16 pupils and one teachers murdered by Thomas Hamilton on 13 March 1996.
The former Scout leader took just three minutes to carry out one of the UK’s worst ever mass shootings, spraying four and five-year-old children with bullets as they gathered for a PE lesson.
Mr Taylor told the Daily Mirror how he burst into the gymnasium to find injured and dead pupils lying in pools of blood and Hamilton, who had shot himself, twitching on the floor.
"It was unimaginably horrible to see children dying in front of you. I felt enormous guilt - more than a survivor's guilt,” he said.
"There was an incredible silence, the air was thick with smoke and there was a group of children standing.
"The first thing we were able to do was to get them out of there. I just couldn't believe what I was seeing.”
"Mr Taylor, who never returned to teaching, had to return to the scene to help police children’s bodies, before writing down his account of events for detectives.
To this day he has been unable to face re-reading the account, or look at a collection of newspaper clippings from the time.
“There is no way we could have adequately prepared for what happened,” Mr Taylor added. "But I felt I should have been able to do more and that guilt lives with me.“
Andy and Jamie Murray were among the pupils inside the school at the time and had met Hamilton at boys’ clubs he ran and when their mother gave him lifts.
The tennis players, who are both world number two in their respective singles and doubles fields, were hidden by their teachers in classrooms.
Several survivors and relatives of the victims have spoken about the massacre for the first time for a BBC documentary as the 20th anniversary of the tragedy approaches.
Amy Hutchison, who was part of the primary one class that was targeted, was shot in the leg by Hamilton but survived her wounds after six weeks of hospital treatment.
"As a child the anger was not there, but looking back now I think 'why?' Why my class, why my school, why my town? Why?” the 25-year-old said.
"I don't remember the pain of being shot, I don't remember the noises or sounds, I just remember my leg turning to jelly and falling to the floor and then dragging myself to the gym cupboard.”
Hamilton was armed with four handguns and 700 rounds of ammunition, sparking a ban on private handgun ownership in Britain.
Alison Ross, the teenage sister of victim Joanna Ross, said the massacre is still hard to accept.
“It needs to be remembered so that everyone's aware that we are still here, we are still getting on with our lives and we didn't just fade into the background either,” she said.
“We still had to power on and push on with our lives.”
Dunblane: Our Story will be broadcast on BBC Two and BBC One Scotland at 9pm on Wednesday.
Additional reporting by PA