Image copyright Getty Images Image caption Policeman on Link Street, Camden, north London, where a 20-year-old man was stabbed in April

Earlier this year, an article in the Sunday Times sparked debate about rising levels of violent crime with a claim that the numbers of murders in London had surpassed those in New York during one month -- February.

My colleague, Dominic Casciani, analysed the figures and found that the newspaper was correct.

In February, the New York Police Department dealt with 11 homicides (suspected cases of murder, manslaughter and infanticide) while London's Metropolitan Police opened investigations into 15 deaths.

But the overall tally for the year to April showed there were more homicides in New York than in London, and that as a proportion of the population they were far higher across the pond.

The apparent blip in the homicide rate and a surge in stabbings -- knife crimes recorded by police forces across England and Wales in 2017 went up by 22 per cent -- prompted an intervention from Donald Trump.

Image copyright Getty Images Image caption There were 141 homicides in New York City in the first half of this year

In a speech to the National Rifle Association in May, the US President said there was "blood all over the floors" of a London hospital.

"They say it's as bad as a military war zone hospital. Knives, knives, knives, knives," said Mr Trump.

"London hasn't been used to that. They're getting used to it. It's pretty tough."

In an interview published in the Sun newspaper on Friday, the President reiterated his view on London's hospitals and said the Mayor of London Sadiq Khan was doing a "bad job on crime."

The Mayor argues that crime has increased across England and Wales. And he says insinuating that the immigrant population is responsible for rising crime in London - as President Trump did - was "preposterous."

So, as Mr Trump visits the UK, and with six months' data for the first half of 2018, how do London and New York now compare?

The figures are pretty clear. In the first six months of this year, there were 80 homicides in London, including one in the City of London which has its own police force.

Over the same period in New York there were 141 homicides - 61 more than London.

As the year has gone on, the initial monthly homicide figures have been updated, as some cases turn out to be non-suspicious deaths and are re-categorised. What that shows is that February was the only month where there were more killings in London (18) than in New York (14): it was indeed a blip.

It is difficult to pinpoint the reason for these kinds of anomalies , but one factor could be the heavy snow in New York in February which has traditionally been linked with reduced violent crime.

What's also noticeable is that since the spike in killings in London in February, the numbers have dropped steadily month-by-month, after the Met established a violent crime task force and stepped up patrols and weapons searches in hotspot areas.

Crime figures must be treated with caution; selecting individual statistics to make a point can be misleading. Although London is experiencing an upsurge in serious violent crime, particularly among teenagers and young men, it is not at the levels that it was in the mid-2000s, and the rate of homicides remains well below that of New York, despite the fact that the Big Apple is a far safer city than it used to be.

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