A mother whose son was stabbed to death while on a night out with friends has called for “zero tolerance” on knife crime, with tougher sentences for those caught carrying a blade.

Becky Beston, whose son Archie Beston was 19 when he was stabbed in Kingston in February last year, spoke as part of a hard-hitting campaign launched on Thursday.

She branded her son’s killer Tyrone Bryan – who was jailed for 19 years for manslaughter – a “coward” and said: “Zero tolerance is what we need, not a 19-year sentence and then you serve maybe 10.”

Speaking at a press conference at Scotland Yard, she added: “You commit a crime and you will then be punished severely for it … you know if you get caught with a knife you get five years and that’s it.”

She and four other mothers who have lost their sons to knife violence in the capital between 2010 and 2020 shared their stories as part of the campaign launched on Thursday.

They are calling on Londoners to call the Crimestoppers charity, anonymously, with any information about knife crime, to help prevent further deaths.

Lillian Serunkuma’s 15-year-old son Quamari Serunkuma-Barnes was knifed to death outside his school gates in Willesden, north-west London in 2017.

His then-15-year-old killer was sentenced at the Old Bailey to serve at least 14 years for murder but Ms Serunkuma, 46, said that for her it is a “life sentence”.

“It’s something that affects everyone who knew him, whether it was his teachers, his friends, the nurses that worked on him, the doctors,” she said.

“Quamari would have been 20 tomorrow, he died three months before his 16th birthday, and I would hope anybody who is out there can see that that’s someone’s life wasted for absolutely no reason.

“Nothing ever justifies taking someone’s life.”

She added: “As someone who has lost a loved one, I don’t want anyone else to be sitting in the position knowing they could have done something to prevent someone else’s family going through what we went through.”

The Hard Calls Save Lives campaign features harrowing film footage of the mothers relieving the phone calls they had to make after their sons were killed.

Lorraine Jones, 48, whose son Dwayne Simpson was stabbed to death at the age of 20 as he tried to save a friend’s life in Brixton in 2014, said: “I had to call my mum. It was the hardest call – I was out of breath and my stomach was tight.

“Even when I was making a call my hands were shaking. I tried it three times, I was just so helpless and weak.

“I had 20 wonderful years with him, and really good memories. But I didn’t realise the impact he had until he passed away.”

The films will be shown on social media, such as Facebook and Instagram, alongside adverts on radio, video display boards and on-demand television.

The campaign is particularly aimed at inspiring women – mothers, sisters, aunts – whose children, siblings, nephews or nieces may be on the fringes of knife crime to make a report if they know someone who carries a knife or where a weapon has been hidden.

Jean Foster, 67, whose son Christopher Foster, a 34-year-old single father, was stabbed to death outside a London pub in 2013, has come up with the rhyme “by keeping quiet, the gangs run riot” in opposition to the “snitches get stitches” code of silence.

“It’s going to be very hard. I mean it’s not an easy call, it’s not,” she said.

“But you don’t want to have to make the call we’ve made, you really don’t. You don’t want to walk in my shoes, it’s hard. And it’s a sentence, it’s going to be a life sentence for me.”

Yvonne Lawson, 50, whose 17-year-old son, Godwin, was stabbed to death in 2010 added: “The message that I really want to put across is this is a troubling problem affecting lots and lots of young people and everyone has a role to play. And together we can solve the problem.”

The campaign is backed by the Metropolitan Police Commissioner Dame Cressida Dick, who praised “the incredibly brave and generous mothers” for their “great strength and great courage”.

“I think for anybody listening to the testimonies of these incredibly brave mothers, it was very moving,” she said.

“And I’ve met many mothers, including several of these before. And not just mothers but brothers, sisters, fathers, partners. It’s awful to hear what happens.

“Of course, prison, and sentencing is very important. It is part of what will deter people from carrying a knife in future. And it is also very important to bring justice for a victim of a knife crime or their family.

“So absolutely, I support our society having a zero-tolerance approach to carrying knives.”

But Dame Cressida said it was “very important” that society did not “turn a blind eye to knife crime”.

“Every life lost is a terrible tragedy, and if we can stop a boy or a young man losing his life on the street through knife crime, then it will be worth somebody giving the information to Crimestoppers,” she said.

Crimestoppers can be contacted anonymously on 0800 555 111 or at Crimestoppers-uk.org.