At about three o'clock, a couple of mothers were chatting at the school gate, waiting to pick up their children from the party.
Then in the corner of her eye, a young nursery-school assistant noticed a slightly built man in his 30s running alongside the fence around the school.
"I didn't think anything of it at first," recalls Lisa Webb, or Lisa Potts as she was then.
"Then I could see he was coming quite fast towards the nursery. I could see this man had a knife in his hand, at first I didn't think that knife was real, but then all of a sudden he hit both of those parents across the head."
It is 25 years today since the man, Horrett Campbell, ran amok with a machete in the grounds of St Luke's CE infants school in Wolverhampton. The laughter turned to tears as the paranoid schizophrenic inflicted horrible injuries on three-year-old Ahmed Malik and Rhena Chopra and Francesca Quintyne, both four. Lisa suffered life-changing injuries as she shielded the children from the heavy blows, and three mothers were also hurt. Pictures of the scattered teddy bears and an abandoned pushchair became a poignant symbol of just how fragile life could be.
The attack lasted just eight minutes, but changed the lives of all involved. For the tiny youngsters who cowered under Lisa's skirt for safety, their childhood innocence was shattered in a matter of moments. For the parents, there would be a nervousness each time they dropped their children off at school.
But the biggest effect was possibly on Lisa herself. The blows from Campbell's machete left her with life-changing injuries to her left arm, which still affect her to this day. And when she returned to her job at St Luke's the following January, she started suffering flashbacks and nightmares, which made it impossible for her to continue work there.
A quarter of a century on, Lisa is philosophical about the impact that eight minutes had on her life. Now a 46-year-old mother of two, she has been married to police officer Dave Webb for almost 18 years. Still living in Wolverhampton, she has spent the past eight years working as a health visitor supporting new mothers across south Shropshire. A trained counsellor, she also continues to run the charity Believe to Achieve, which she founded in 2002 to help raise the esteem of schoolchildren.
"It's impossible to say whether my life would have worked out differently if it hadn't happened," she says.
"I am now working with children in a caring role, and I love that, but whether what happened influenced that, I don't know.
"I was determined I didn't want to be defined by that eight minutes of my life, I didn't want to be a professional machete heroine.
"But I wanted to get something out of the experience rather than seeing it as entirely negative.
"It's made me the person I am."
One of the hardest moments came when her oldest son Alfie, now 17, started his first day at nursery.
"I was terrible," she admits. "You try to look at it logically, and think that something like that is not going to happen again, but when I first let go of him, it was very difficult."
Lisa has kept in touch with Francesca and Ahmed, and is very proud of the successful careers they both went on to achieve. She is particularly close to Francesca, or Fran as she now prefers to be known, who trained as a clinical psychologist with a view to preventing people with similar illnesses to Campbell from committing such acts in future. Fran has little memory of the attack, which saw part of her ear cut off, although the scar to her face and two metal plates holding her jaw together serve as a constant reminder.
The attack came less than four months after the Dunblane massacre, which saw 16 children and one teacher killed when Thomas Hamilton opened fire on a primary school gym class. It later emerged that Campbell's actions had been influenced by those of Hamilton and Australian serial killer Martyn Bryant, who shot 35 people in Tasmania.
Recalling the day in question, Lisa says it had been a particularly joyous time until Campbell arrived.
"It had been a happy day, the sun had been shining, and we had two picnics, one for the younger children in the morning, and one for the older nursery children in the afternoon," she says.
She felt no pain when Campbell struck his first blow across her left arm.
"I think the adrenalin was pumping round my body," she says.
"Francesca was right next to me because I had children holding on to my skirt in fear not realising what was going on. I remember the knife coming down as if it was going to hit Francesca on the neck. I put my hand across her face and he cut her straight across the face, neck and ear."
"Ahmed came running towards me with his sister. I tried to pick him up, his sister was screaming, and as I picked him up Campbell cut me across the right hand and straight across Ahmed's head.
"I grabbed Ahmed and pushed him inside the school with the other children. The man was behind me and in the doorway with me. I did not realise I could not shut the door because my right hand was so badly injured.
"His foot was in the doorway. I was stuck in a very small corner with dressing up stuff and toys. I had got all those children in front of me and he hit me across the back, twice.
"I remember grabbing as many children as I could and, as he turned round, I started running with all those children to get out of the main building. The last blow I felt was right across the back of my head which is when he fractured my skull.
"I continued to run and looked back to see where he was. At that point he put away the machete, jumped the fence and was gone."
Campbell, who was 33 at the time, lived in the now-demolished Villiers House tower block overlooking the school. He watched the aftermath of the incident from the roof of the building. He was arrested the following day after being found hiding in a broom cupboard in the block.
Described by police as 'an occasional customer' before the attack, he had a sinister interest in Nazi politics, and had decorated his machete with a swastika.
During the attack he wore a deerstalker hat which he had styled to look like a German helmet, with an iron cross drawn onto it and screws poking through the side like horns. He told police it gave him courage.
Campbell was convicted of seven charges of attempted murder, and ordered to be detained indefinitely in a secure mental hospital.
While Lisa is proud of her achievements and happy to have been able to use her experience to help others, she says she still wishes it never happened.
"There was a time roundabout 1996 and 1997 when I was getting all these awards, I think it was 21 awards in total, including the George Medal, and people would say 'I bet you love all this'," she says.
"I used to tell them I would have gladly given it all up if it had never happened.
"I would never have wanted all that to happen, neither for me, nor for the children."