Gordon Brown has urged communities to "rise up" across Britain to convince young people they do not need to carry knives.

The Prime Minister said "decent people" needed to send the message that weapons are not acceptable on the streets, in the same way gun crime, bullying and racism had been tackled in the past.

Speaking at the opening of the Edinburgh International Book Festival Mr Brown admitted knife crime was "the biggest problem" being faced in some cities and insisted attitudes among young people needed to change.

Mr Brown told the audience that the Government could not tackle the increasing problem of knife culture alone.

“Young people are thinking it’s acceptable, fashionable, necessary for them to protect themselves, to carry a knife," he said.

"Just like we made guns unacceptable, we should make knives unacceptable.

“You need not just young people, but parents and other people to say that knives in Britain, like guns, like bullying, like racism, all these things are unacceptable.

“We have to to persuade people, it’s not a thing Government can do only. People in the community have got to, in a sense, rise up and say this is unacceptable behaviour.”

So far this year 22 teenagers have been killed in London, 19 of them stabbed, while last year 27 young lives were claimed.

Last month Frederick Moody, 18, was stabbed to death near his south London home to become the latest stabbing victim in the capital.

“I think in Britain we’ve got to make it as unacceptable to carry knives," the Prime Minister continued.

"I think most decent people in our country would want to do that and I think what you will see over the next few months is this sort of campaign, which is led not just by Government but people in the country to say ’get knives off our streets - it’s completely unacceptable’.”

On Wednesday night 18-year-old Ryan Bravo became the 22nd teenager to be killed in London this year when he was caught in the crossfire of a shooting as he visited a supermarket in Walworth, south London.

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