A couple of years before I retired as an officer, the Metropolitan police carried out a survey on knife crime across the capital’s schools. One point came through loud and clear: that many young people carried knives out of fear for their own safety. This echoed the anecdotal evidenced I observed during my 17 years’ work on developing educational responses, and was especially true where young people lived in crime hotspots, invariably linked to street robberies, crack cocaine drug-dealing and the associated “postcode” gang affiliations (though only about half of violence is gang-related).

With more than 50 murders in the capital this year, there has been a renewed focus on gun and knife crime. It is a complex issue and divides opinion over police tactics and community responses.

Added to my experience of policing over three decades, it seemed to me that if young people did not feel safe and secure, they could be swayed by peer pressure or crime gangs into carrying knives, and so knife crime would increase. And if vulnerable youngsters, often traumatised by exposure to violence, directly or indirectly, are not given any emotional or psychological support they can internalise their emotions, only to erupt with the minimum of provocation, resulting in violent episodes and tit-for-tat reprisals. If this is overlaid by the misuse of drugs, alcohol, social media and violent music, you have a cocktail of volatility that can spread like a disease.

Sadly, services aimed at safeguarding young people have been drastically cut by the government’s austerity strategy. Therefore it shouldn’t be a shock that knife crime increased by more than 25% last year, following gradual increases beforehand. And the devastating consequences have been the increasing number of deaths and life-changing injuries.

It shouldn’t be a shock that knife crime increased by more than 25% last year

When I was the deputy borough commander of Hackney, east London, from 2004 to 2007, I was in charge of the safer neighbourhood teams, whose purpose was to build trust and confidenceand improve two-way information sharing. I also had safer schools officers in each of the borough’s secondary schools. These all generated significant intelligence on why and where violent crime was occurring, and helped in crime prevention.

I realised then that we could not arrest our way out of the knife crime problem, since it bore no correlation with stop and search. This is still the case today, according to Home Office data: the proportion of stop and searches that end in arrest for carrying a knife is less than 5%. The Met undertook 300,000 stop and searches last year (more than 50% of all stops nationally); and given that black people are eight times more likely to be stopped than white people, there’s little doubt the resentment it causes has an impact on community intelligence, an essential ingredient in effective policing. Added to this, the safer neighbourhood teams have now been drastically cut under austerity, like many police resources. The Met has fewer than 30,000 officers for the first time in 15 years, and has 700 fewer detectives than it had a few years ago.

The World Health Organization has for many years advocated a public health approach, which has significantly reduced violence in many cities globally. Glasgow, once known as the murder capital of Europe, was able to cut knife crime by 40% by recognising trauma in young people as adverse childhood experiences (ACEs). This put young people at the centre of its strategy, caring for them and not trying to scare them with chest-thumping rhetoric around enforcement.

For the past year I have been working on an all-party youth violence commission, bringing together academics and practitioners, and looking at how the public health approach can be adapted in London. Above all, I believe there is an urgent need to fund safeguarding organisations, and improve their engagement with and support for young people. If we start with that we will at least have a chance to deal with violent crime – a crisis that at the moment only seems to be getting worse.

• Leroy Logan is a former superintendent in the Metropolitan police and a former chair of the Black Police Association Charitable Trust