It was early evening on a beautiful day. The father was in the sitting-room reading the paper, the children were playing. The phone rang; the mother answered. It was the police to say their 16-year-old son had been assaulted.

When they got to the hospital, he was dead. He had been slashed across the throat, following a football match.

The mother became hysterical. She put her fist through a window.

This is one of the “real life stories” related by the victims and the perpetrators of knife crime in a 20-minute DVD shown by Medics Against Violence.

The organisation was set up in December by doctors tired of dealing with the consequences of the violence on Scotland’s streets. Now, with Pounds 80,000 of Scottish Government money, they have started to take their frequently shocking and heart-wrenching experiences into schools to educate youngsters about the stark consequences of fighting.

So far, 38 schools in Glasgow and Renfrewshire have asked the organisation to talk to their pupils, while Inverclyde Council wants the doctors to visit all seven of its secondary schools.

“Healthcare workers see the outcomes of these attacks every day,” says Christine Goodall, an oral surgeon at Glasgow University dental school. “We see how they can ruin lives, not only of the victims, but of their families and friends.”

The doctors begin their lesson at Castlehead High in Paisley with the film and then break the S2 pupils up into three groups, each led by a doctor. They are asked to discuss the best and worst place to get stabbed; the good and bad things about carrying a knife; and how long it would take a person to bleed to death if stabbed in a leg artery. They are also asked to consider how long the ambulance would take to reach them.

The answers to the final two questions turn out to be seven and eight minutes respectively.

“What is the result?” she asks.

“You’re dead,” answers a pupil.

Meanwhile, a group of boys decides the “meaty” backside would be a pretty safe place to be stabbed. Maxillofacial surgeon Rodger Currie soon shatters the illusion.

“What happens to the stuff you put in here?” he asks, pointing to his mouth. “Where does it come out?”

The tube that takes it out does not go in a straight line; cut that and everything starts leaking, the body becomes septic, and the patient dies. “I’ve seen it,” he says.

For the medics involved, this is about doing something at the beginning instead of being there at the end, says psychiatrist Justin Crean, who deals with the consequences of violence, treating patients with post- traumatic stress disorder. “The people involved in violent crime are just as likely to become the victims psychologically,” he says.

Michael Murray, a neuro-anaesthetist at the Southern General Hospital in Glasgow, admits he is battle-weary. “This is just a chance to influence something - to have any kind of impact at all,” says Dr Murray, who was on call on the day of the Dunblane massacre. “There’s a quote that goes something like: `For evil to prevail, good men just need to do nothing’.

“I see seven or eight people every day needing their faces rebuilt and brains fixed - or not, as the case may be.”

Nine months ago, he was involved in an operation on a man in his 20s. The patient has not left hospital since. “He can dribble without assistance, that’s about it,” he says.

Oral surgeon Siobhan Kyle, meanwhile, recalls a patient who died from a 3cm laceration in his cheek.

Teacher John McFie, who takes the S2 life skills class the medics are teaching, feels it is significant that the lesson is being delivered by doctors. “I think the pupils felt quite honoured,” he says.

Mr McFie has seen a lot of talks of this nature, but because of the graphic images - the film contains violent scenes captured on CCTV cameras - and the real stories, this one is particularly hard-hitting, he says.

That appears to be reflected in the class’s reaction. There is some sniggering initially but quickly the pupils become engrossed.

Asked what the most powerful part of the lesson is and the reply from the class is the story of Scott Breslin.

“You didn’t notice he was in a wheelchair until the camera zoomed out,” one boy says.

Scott, who was involved in gangs, was stabbed in the neck seven years ago when he was just 16. The knife cut his spinal cord and he was paralysed from the neck down.

“My life has changed from being a young boy, about to start a new job, with the whole world in front of me,” he says in the DVD. “Everything has to be planned now. I can’t even go to the toilet by myself nowadays.”

Also featured in the DVD is a young man serving time in Polmont Young Offenders Institute for killing a man “with weapons” when he was 15.