Numbers will prompt significant concern with the rise in knife offending driven by a 34 per cent increase in blade robberies 14,626 knife offences were recorded by police in the capital over the 12 months to the end of December (PA) Martin Bentham @martinbentham1 minute ago Knife and gun crime in London both leapt by 20 per cent last year amid a surge in blade robberies, teenage homicides and firearms offending, official figures revealed today.