PM's Promise On Knife Crime

Gordon Brown says the Government will take "any legislative measures necessary" to tackle knife crime, as Sky News reveals the extent of the problem.Speaking at the G8 summit in Japan, the Prime Minister said it should be "completely unacceptable" for young people to carry a knife on the streets.

It comes as a survey of police officers has found more than 80% believe knife crime has got worse in the last five years, in stark contrast to official statistics.

According to the British Crime Survey, the level of knife crime in the UK has remained stable over recent years.

But a new report published by the Policy Exchange has labelled those findings "misleading", saying they bear no relation to the reality experienced by communities and police forces across the UK.

Speaking to Sky News, one of the report's authors, Jonathan McClory, said: "We polled 1,200 police constables and they've all said that gun and knife crime is much worse than official statistics are saying.

"We need to look at the long-term trends not the year-on-year trends. It's quite easy to manipulate year-on-year shifts which is I think what the Home Office have done".

The report comes as knife crime is already under the media spotlight. So far this year, 15 people under the age of 20 have been stabbed to death in London.

That is just one short of the 16 killed with knives in the capital during the whole of last year.

Just last night Wiltshire Police attended a knife-related incident in which a 13-year-old suffered minor injuries and another 13-year-old was arrested.

Last week, the Metropolitan Police announced they had increased the number of officers working in their specialist anti-knife crime task force - Operation Blunt 2.

Sky News has become the first news organisation allowed out on patrol with these units.

Last night, a fleet of vans from the Met's Territorial Support Group launched a high-visibility stop-and-search operation in Thornton Heath, south London, where 16-year-old Shakilus Townsend was fatally stabbed last week.

Over several hours, the teams carried out numerous stops. In one incident, a group of young men were seen acting suspiciously in a doorway.

When officers searched them, they found 25 wraps of cannabis in a vehicle belonging to one of the men. He was arrested for possession of a controlled substance with intent to supply.

Sergeant Darren Birmingham told Sky that drugs were linked into a vicious cycle, which often ends in knife or gun violence.

A short distance away, the team stopped three 14-year-old boys. One was carrying the sharp metal shaft of a dismantled umbrella.

When questioned, the boy revealed he had been slashed in face by another youth a week earlier. The blade narrowly missed his eye.

He is one of hundreds of youngsters across Britain whose brush with knife crime is not recorded in official statistics.

It is one of the errors highlighted by the Policy Exchange in the way knife crime figures are collated.

Under 16s are not included in the British Crime Survey but the latest hospital admission figures show the number of children under the age of 16 being treated for knife wounds has increased by 62% in the last five years.

The Royal London Hospital has been collating its own figures on patients treated by their trauma unit for serious and potentially serious knife wounds.

Consultant trauma vascular surgeon Mike Walsh said: "Our experience here is that the number of people suffering knife injuries is increasing year-on-year.

"If we took the figures for 2007, we had a total of 185 injuries in the year, so far in the first half of this year we've had 140."