New figures published over the weekend suggested that an alarming tipping point had been reached when it came to comparisons of UK and US crime rates.

The Sunday Times compared the crime figures of London and New York, and found that for the first time in modern history the murder rate in the UK capital was higher than that in the Big Apple.

But how valid was the comparison, and what was the truth behind the statistics?

Why compare London with New York anyway?

In statistical terms, it works because the two cities have roughly the same population, (both slightly north of 8.5m) allowing a relatively easy comparison of murder rate per head of population.

And for those with longer memories, the idea of London having a higher murder rate than New York is particularly scary because in the recent past the American city was a byword for violent crime.

It hit a terrifying record of 2,245 murders in 1990, equivalent to six people being killed every day for a year.

So is it really true that London’s murder rate is now higher than New York’s?

Yes, but only if you look at the last two months – which some commentators think is way too short a time frame.

The Metropolitan Police has confirmed that it recorded 15 murders in February, while in the same month the New York Police Department (NYPD) recorded 11 killings.

In March London also had more murders, albeit by a very slim margin: 22 to New York’s 21.

But as soon as you start to look beyond the relatively narrow confines of those two months, the statistics start to come out in London’s favour.

The Met says there were 8 murders in London in January, which compares with 18 killings in New York during the first month of the year.

Taking into account two murders that have occurred in London in April, so far in London there have been 47 murders in London, compared to the higher running total of 50 in New York.

So were February and March 2018 just blips?

Possibly. While those two months may have been the first times in recent history that London had a higher homicide rate than New York, the year-on-year statistics are still firmly suggestive of the UK capital being the less murderous city.

There were 116 murders in London in 2017, fewer than half New York’s annual total of 290.

The disparity seems even more marked if you look slightly further back, albeit with the caveat that the way the Met presented its data for these years does not allow comparison of exactly the same 12-month time periods.

In the calendar year of 2016 there were 334 murders in New York. In the financial year 2016-17 (1 April 2016 to 31 March 2017) there were 102 murders in London, suggesting – but not proving - that at that point the UK’s capital’s murder rate for any given 12-month period was less than a third of New York’s.

Similarly, New York had 352 murders in the calendar year 2015, while London’s Metropolitan Police recorded 109 homicides between 1 April 2015 and 31 March 2016.

When reporting on The Sunday Times story, The Independent noted that London remains substantially the safer city overall.

So what is going on with these murder rates?

One way of looking at this is to see it not so much as London getting massively more violent, but rather New York achieving an astonishing drop in its murder rate.

The tally of 290 New York murders in 2017 – while still much higher than London’s corresponding total – has been hailed in America as a hugely encouraging breakthrough. It is definitely the lowest annual murder total since comparable New York records began in 1994 and it is being reported as the city’s lowest number of homicides since the end of the Second World War.

It is also indicative of the fact that since recording 2,245 murders in 1990 and 1,905 in 1989, the city has achieved great things in tackling violent crime – albeit that the precise reasons for the success are hotly debated.

London’s recent history, meanwhile, has been mostly one of steady if unspectacular drops in the murder rate, from 181 homicides in 2005 to 155 in 2007 and 101 in 2013.

When the annual London murder total dropped to 93 in 2014, it was hailed as a great success, the first time since the 1960s that there had been fewer than 100 homicides in a year in the capital.

Since then, of course, London’s annual murder totals have increased: from 93 in 2014 to 116 in 2017, a rise of nearly 25 per cent.

It’s worth remembering, though, that if you look over a time frame of a decade, there were 25 per cent fewer murders in the capital in 2017 than in 2007.

So is there nothing for Londoners to worry about?

Sadly it’s not that simple. The 2018 London figures highlighted by The Sunday Times might be an early warning sign that the capital is in for a historically bad year for murder.

There were 45 murders in London in the first three months of 2018. If that rate of killing continues, London will amass a total of 180 homicides in 2018, the kind of death toll not seen since the 181 deaths recorded in 2005.

And there are – admittedly highly tentative - signs that the killing rate is not abating. Since The Sunday Times first published its story there have been two more murders in London – the stabbing of a 20-year-old man in Wandsworth on Sunday and the shooting of 17-year-old Tanesha Melbourne in Tottenham on Monday.

What is also alarming is that the statistics seem to suggest that young people are being killed in increasing numbers, in a trend related to what looks like a spike in knife crime.

There have been 31 fatal stabbings in London so far this year, 30 of them in the first quarter. As The Independent has reported, that equates to a rate of a deadly stabbing in the capital every three days. It also puts London on course to record 120 fatal stabbings in 2018, a 50 per cent increase on the 80 deadly knifings that occurred in 2017.

And nine teenagers have been killed so far this year. In the first quarter of 2018 there were eight teenagers killed, at least six of them by stabbing - (the cause of death has yet to be established in the case of one teenager).

Those figures could be extrapolated to suggest that London is on course to record 32 teenagers killed in 2018, with 24 of them stabbed to death. This would compare with 26 teenagers killed and 20 teenagers stabbed in 2017.

And if it turns out that 24 teenagers have been stabbed to death by the end of 2018, it would be a return to the levels of 2008, when 23 teenagers were killed by a knife in the capital, and newspaper headlines spoke with alarm about a "knife crime epidemic".

It is, however, important to remember that extrapolating from three months of data to suggest what might happen over the next nine months is very far from being a foolproof, scientific method of prediction.

It could be that after a bad first three months of 2018, things improve over the next three quarters of the year.

So how worried about murder should I be in London and New York?

Probably a lot less worried than in other world cities.

Metropolitan Police spokespeople have again stated that “London remains one of the safest cities in the world” – and they probably have a point.

London’s annual murder totals are – so far – below those of New York.

And as New York reduces its murder rate, it can point to other US cities that seem to be far more violent.

New York’s murder rate in 2017 was the lowest of the five largest cities in the US. Its 290 murders in 2017, for example, compared with 644 killings in the same year in Chicago - a city with less than a third of the Big Apple’s population. Which meant that while New York’s murder rate was just over 3.4 per 100,000 people, Chicago’s was 23.8.

The contrast was even more marked in 2016. New York had 334 homicides, while Chicago recorded 762 killings, its highest murder total in 19 years. That worked out at 27.7 homicides per 100,000 residents – yet even that was far better than the murder rates of some cities in, and especially outside the US.