By ITV News Multimedia Producer Narbeh Minassian

A trip to the shop to buy snacks after school turned into a heroic life-saving effort for three schoolboys.

Shawn Young, then 12, was heading home with then-13-year-old Devonte Cafferkey - his friend since nursery - and Sammy Farah, then 14, when they learned a young man was causing a disturbance on the bridge they cross every day.

“It was just a normal day coming home from school, we were going to chill at Devonte’s house," Shawn, now 14, told ITV News as he recounted the events of September 21, 2017.

"We were going to the shops for some snacks and as we walked up someone told us, 'There is a crazy man'."

It soon became obvious the man was trying to end his life over a built-up stretch of the A10 in Waltham Cross, Hertfordshire.

Rather than retreat, walk on or even join others in watching the grim scene, the boys reacted.

“Devonte and Sam went to hold him but it kicked in that we can’t do this by ourselves, so I went to get help, the road was quite busy that day.”

It was Thursday rush hour and drivers had no idea what was unfolding on the overpass above them - until Shawn ran into the traffic in a panic.

“I didn’t know what to do, I was just knocking on neighbours’ doors and I stopped cars," he continued.

"I ran so quickly into the road that a car nearly hit me.”

Behind the wheel was Joanne Stammers, 49, who remembers almost colliding into Shawn as she drove away from her nan’s house.

Joanne Stammers left her car to help.

Seeing the “absolute fear” in his eyes, she stopped and rushed out of the car to be told: "Please, please help."

Back on the bridge, other teenagers had begun filming the struggle on their camera phones while Devonte and Sammy battled to hold the man.

Devonte had grabbed the man’s leg through the railings while Sammy held his arm – both telling him not to jump as he faced them from the other side.

“He just kept saying let go,” Sammy, now 16, told ITV News.

“When I ran over I was scared he was going to attack me. I didn’t want to see him die.”

During the struggle, the man handed his car keys and mobile phone to the boys, telling them: "If it rings, don’t answer it."

Joined by another stranger, James Higlett, and with Joanne taking the lead, the boys said they held the man back for around 10 minutes until police arrived and closed the road.

Devonte then helped an officer to handcuff the man.

Sammy Farah (left) and Shawn Young recalled the day to ITV News two years on.

While the fire brigade soon arrived with a ladder, Joanne said getting the suicidal man down was far from straightforward.

“He [the man] was trying to throw himself backwards and they were leaning back and all their weight was trying to hold him back,” she recalled of what proved a painful effort.

Living with Klippel–Trénaunay syndrome, a rare disability that makes her highly prone to blood clotting, her arms were later covered in bruises.

“He was fighting the whole time, he was not willing to talk or anything, he just really wanted to die," Joanne said.

“He kept going to pass out and that added to the weight. Police managed to (secure him) and then it was just a fight to hold him.”

With police confident they had regained control of the young man, they eased him down with the help of a cherry picker from the fire brigade and an ambulance drove him to hospital.

Police then took the boys’ details, before the three continued - as they had set out - on to the snack shop.

The boys walk over the bridge every day.

Finally reaching Devonte’s house, they told his mum what had happened but the next day decided not to tell any of their other school friends.

Carol Young, Shawn’s mum, only found out about her son’s heroics the morning after.

“Normally, I will tell my children ‘why didn’t you do this or that’ but there was nothing I could fault this time,” she said.

“And I said 'you have done really well' and I was very proud of their actions - what they did was textbook... these boys could have walked by and laughed as other boys would."

While their intervention saved the man, 5,821 other lives were lost by suicide in the UK in 2017, according to the Office for National Statistics.

That figure rose to 6,507 suicides in 2018.

Three-quarters (4,903) were men.

The bridge stands high over the A10 in Waltham Cross.

Reacting to the figures, Samaritans chief executive Ruth Sutherland said: “Every single one of these deaths is a tragedy that devastates families, friends and communities.

“We hope (the rise from 2017 to 2018) is not the start of a longer-term trend – it’s crucial to have a better understanding of why there has been such an increase.

“We know that suicide is not inevitable; it is preventable, and encouraging steps have been made to prevent suicide, but we need to look at suicide as a serious public health issue.”

Only the coincidence of the three schoolboys slowly ambling their way home prevented the young man in Waltham Cross from adding to those figures two years ago.

Proud mum Carol said: “The boys have been really humble about it. There has been negative press about young black boys but they did something so positive and the outcome is this young man seems to have carried on with his life.”

The man was grateful to the boys and visited them once he was out of hospital.

He brought with him gift cards for JD Sports and Shawn said he still sees him around Waltham Cross, though he hasn’t approached him.

The chief inspector of the area’s police at the time, Ian Butler, recommended the boys for awards, which they were given by the Royal Humane Society.

Former chief inspector Ian Butler recommended the boys for awards. Credit: Hertfordshire Police

“For me as a police officer, generally a lot of the stories that we get involved in are negative,” he told ITV News.

“And every now and again you get that golden nugget of community spirit that shines through that shows members of the public, who are often caught up in their daily lives or too fearful to do the right thing, can stand up and help.

“They didn’t put themselves in immediate danger but, having said that, it was on a high bridge with somebody showing behaviour they are probably unaccustomed to.

“So for me it was a really golden nugget that you don’t see enough of sometimes.”

Recognition was due whether the boys wanted it or not and soon all their friends found out after they appeared on This Morning before the story went worldwide.

The three were even flown out to Los Angeles to appear on The Steve Harvey Show.

Joanne Stammers still sees the boys around from time to time.

Two years on, Shawn and Devonte have just started in Year 10 while Sammy, two years their senior, is beginning studying maths and sports at a college in London.

Joanne still sees them around near her grandma’s house and says hello.She said she thinks the boys are “amazing”.

Sammy said he was “just happy” to save a life.

Shawn added that his mum’s friends always point out the positive image he and his friends have given to their peers and, in particular, young black boys.

Reflecting on their impact, Shawn said friends had told him they hoped, if they ever came across similar tragedy unfolding, they would know how to respond.

“I think we have inspired people to go help rather than get their phone out."

If you are in distress or need some support, the Samaritans are available 24 hours a day on 08457 90 90 90 or visit their website.

For those in the Republic of Ireland, the number is 1850 60 90 90.