Tom Wolfe’s best-selling novel of the 1980s, Bonfire of the Vanities, painted a chilling picture of New York as a crime-ridden metropolis where death stalked the sidewalk and murderous, random violence was a way of life.

Back then the Big Apple was known as the ‘Rotten Apple’ and its reputation haunted it for decades. London by comparison was a haven.

No longer. For the first time since crime records began, the murder rate in London has overtaken that of New York.

This is due in part to New York becoming a lot safer, following a zero tolerance approach instituted by then mayor Rudy Giuliani, and the famous ‘broken windows’ policy.

The spate of murders in London in recent weeks is a shameful milestone and necessitates an urgent debate

No misdemeanour was deemed too minor and police were present 24/7 in problem areas. As a direct result, murders there have fallen by 87 per cent since the 1980s. In 1990, 2,245 people were killed; last year the figure was 286.

Of course, there are many cities in the US which have not succeeded in cutting the homicide rate, and overall Britain remains a much safer country than America.

Nevertheless, the spate of murders in London in recent weeks is a shameful milestone – and we need an urgent debate about the contributory factors.

Metropolitan Police Commissioner Cressida Dick said interactions between individuals and gang members on social media were helping to inflame minor disagreements and grudges until, all too often, they ended in stabbings or shootings. I am sure she is right.

However, there is another major factor behind the surge in deaths which is staring us in the face.

Between 2010 and 2014, knife crime was going down. In that time, reported offences involving a knife or sharp instrument across England and Wales fell from 32,900 to 26,000.

Cressida Dick said interactions between individuals and gang members on social media were helping to inflame minor disagreements

Then, in April 2014, Theresa May, then Home Secretary, made a speech in which she ordered police to observe new rules on stop and search.

She had been moved, she said, by figures which showed people from a black or other ethnic minority background were seven times more likely to be stopped and searched and she ordered police to reduce the number of stop and searches which did not result in an arrest.

In future, she said, an officer would use stop and search powers only if he or she believed a crime ‘will’ take place rather than when they believed it ‘may’ take place.

The new rules had a dramatic effect. In 2013/14, there were 904,038 stop and searches. In 2016/17, that number fell to 303,845.

But, as stop and searches were curtailed, a worrying – if largely predictable – thing happened.

From 2014, the rate of knife crime began to rise again for the first time since 2010. By 2017, the number of knife offences across the UK had risen to 34,700. There was, of course, some truth in what Theresa May said.

The black community did undoubtedly feel they were being singled out – guilty of ‘walking while black’. For law-abiding individuals who felt they were being targeted, it was an upsetting, humiliating and unsettling experience.

And when people are treated unjustly, it is counter-productive in the fight against crime. Officers will always find it difficult to win the co-operation of a community that feels under siege.

However, there is also evidence to suggest Mrs May could have been exaggerating the problem.

In April 2014, Theresa May, then Home Secretary, made a speech in which she ordered police to observe new rules on stop and search

Last week, Alasdair Palmer, her speechwriter at the Home Office, revealed that officials had commissioned – but then ‘forgotten about’ – a study from Wolverhampton University which found that while it was true a disproportionate number of black people were being stopped and searched, it wasn’t true to say they were being targeted.

There were simply more black people out on the streets in areas where knife crime was a problem.

None of this changes the simple fact that if we are going to stop young men killing each other, we have to take knives off the street.

The best solution is to find a way of searching for knives which is not hostile and which does not leave people feeling they have been singled out. Miss Dick has spoken previously of the benefits of police body cameras.

For the black community, the recording of interactions serves as reassurance that officers will not abuse their powers. For police, it provides a ready source of evidence when their integrity is called into question.

A more radical solution would be to make searches a routine procedure. No-one feels they have been singled out by being made to walk through an airport scanner, for example, because everyone has to do it.

When my son was in Beijing last year he sent me a video of himself heading down into the city metro system where everyone had to walk through a scanner.

Perhaps something similar could work here.

Whatever the police do now, it is clear that scaling back stop and search has been a dreadful mistake. They need to make getting knives off the streets a priority – and that means, one way or another, increasing the number of people being searched.

More police on the streets might help, too. It worked in New York.

In Britain, the number of police officers has tumbled from 143,734 in 2010 to 123,142 now.

New York doesn’t have a hugely greater number of police officers than London – 40,000 against London’s 32,000 (the cities are a similar size), but when I visited New York the police were certainly a more visual presence on the streets.

It is an approach we would do well to adopt in London.