Only a generation ago, most disputes among groups of youths were settled with fists.

While such thuggery was inexcusable, its results were normally confined to broken noses and black eyes.

Now altercations frequently involve lethal force – and the knife is the weapon of choice.

Yesterday, Cambridgeshire Chief Constable Julie Spence told MPs how her area has faced an influx of Iraqi Kurds, Poles and Lithuanians, who habitually carry knives.

Anyone following the upsurge of stabbings in London can hardly have failed to notice how often the perpetrators turn out to be of non-British origin.

It is becoming clear our new knife culture is largely an imported phenomenon. When the use of knives in fights was rare, Britain was exceptional.

Across swathes of the globe, stabbings have always been common. The failure to control immigration from places where life is cheap has led to a cheapening of life here.

Homegrown thugs are now adopting the carrying of blades.

Reversing this trend will require singlemindedness and determination on the part of the Government, the police and the courts. But there is little indication that they are up to the task.