It’s the call that you dread.  Another teenager, barely 17-years-old, stabbed to death on the streets of Croydon. Aren Mali was the second teenager killed in Croydon in the last three months.  And many more stabbed but survived.

I cannot imagine, as I look at my children, what it must be like for a parent to get that call. But we know that behind every headline is a wrecked family, and a community in shock.  And a generation of young people becoming increasingly anxious and desensitised to the possession and use of lethal weapons.

Is isn’t just happening down dark alleyways or in the shadows.  This is in our town centres, in our communities.  Studies have shown that 50% of London’s kids know somebody who carries a knife.  Imagine what that does to your childhood, to your sense of anxiety even if you and your friends are nothing to do with knife carrying.

Croydon might be where the harsh realities of knife crime are most visible, but this epidemic isn’t limited to one or two postcodes. Knife crime is up across the UK – from Aberdeen to Cardiff to Colchester.   Over 1,200 young people were stabbed across London last year, and the symptoms are growing across the UK, with criminal gangs extending ‘county lines’ into cities and towns nationwide.

Knife crime has become a public health crisis amongst our young. And it’s becoming more complicated: this isn’t just ‘kids in gangs’ who want to make money. In fact much of London’s knife crime isn’t gang related.

Nor is it solely about policing budgets, though cuts to community police numbers  (Croydon has lost over 80% of our PCSOs) have undeniably had an effect.  The causes spread from lack of job opportunities, training and education to mental health cuts, the closure of youth services and .  This is an iceberg of issues of which the tip is knife crime.

I’ve been pushing the Home Secretary to prioritise this epidemic amongst our young people It feels like time and again ministers or politicians have spoken out to say “enough is enough”.  The government will announce yet another well-meaning but underfunded ‘initiative’ or promise to ‘look again’ at sentencing.

But small-scale, short-term interventions are simply not going to come close to solving this crisis. The government’s flagship ‘Ending gang violence and exploitation’ programme received just £99,000 funding for this year.  To put that into context, the Home Office annual budget is around £10bn.

We need government to develop and properly fund a cohesive, 10-year knife crime strategy which coordinates work across departments, agencies and councils. This is a UK wide problem which requires a UK-wide response. The model should be the Labour government’s hugely successful teenage pregnancy strategy which produced a 51% drop over a 16 years and is now being used as a blueprint by the World Health Organisation.

What should be in this strategy? The positive and at the same time, depressing thing is that a lot of the answers we already have. We can fix this. But at various stages, where adults should be intervening in the lives of troubled young people, they aren’t. Sometimes that’s because of lack of resources, and sometimes it’s because different agencies aren’t working together as well as they should.

I spent much of my summer talking to people in Croydon – charities, agencies and young people themselves – hearing about why knife crime has doubled here in just one year.  I met towering figures in the community who are giving their all to fight this problem and some amazing young people who against the odds have turned their lives around.

But I also heard stories which broke my heart. Two police officers battled to save a life by putting their fingers in a wound to stop the streaming blood. He survived despite losing six pints of blood. But a week later he was picked up with a knife as he went looking for retribution.

I heard of young people who have been in care all their lives and find their only sense of belonging in a gang; of girls whose boyfriends ask them to carry their knives and they do it because they believe its what is expected of them.  Horrific images of stabbings, of strippings, shown far and wide on social media.

Funding cuts across our public services – policing, youth work, education and health – have left a huge vacuum that social media and criminal gangs are filling.

Social media is undeniably fuelling an escalation in the cycle of violence among young people. People repeatedly tell me how Snapchat, YouTube and Instagram are being used to document attacks and threats between rival groups.

These platforms need to take more social responsibility for the way their products are being used. And the government must take the same strong approach it applies to extremist content online.

Schools are on the front line. Every agency I have spoken to reports increasing levels of what they call ‘managed moves’ or expulsions, often for children with undiagnosed mental health or behaviour disorders, where the school simply cannot cope or does not want the child in their school.

I recently surveyed Croydon headteachers about the impact of funding pressures on their schools. 92% told me they had been forced to cut staff, and 85% said they had been forced to cut support for children with special educational needs. How can we expect our schools to support vulnerable or challenging pupils with ever diminishing resources?

Moving difficult children on – to other schools or to Pupil Referral Units (PRUs) is a very worrying trend. We are telling kids that they’ve already been given up on. That they need to be kept away from their peers, instantly causing them to feel detached. One charity described to me the “straight line between PRUs and gangs.”

We need to decide if we care enough to take this head on and tackle it for the long term.  The police can’t arrest us out this problem.  They can lock people up, but the problems will continue unless we look at the bigger picture and act.  We need a strategy that tackles the widespread factors. The truth is we haven’t got one.