The head of London's police force has backed new legislation which will see people who repeatedly carry knives automatically jailed. 

Adults convicted more than once of being in possession of a blade will face a minimum six month prison sentence from July 17, the Ministry of Justice has announced. 

Metropolitan Police Commissioner Sir Bernard Hogan-Howe said it is "no secret" that he supports the new law which was passed earlier this year following a campaign by former Conservative MP for Enfield North Nick de Bois.

Under the new 'two strikes' sentence, 16 and 17 year-olds will face a minimum four-month detention and training order.   

Despite official figures which show a drop in knife crime offences, the capital has seen an increase in stabbings in recent months, Sir Hogan-Howe said. 

He said:  "Knives kill.

"People carrying knives are a threat to all of us - my officers see that at first hand.

"A simple guarantee that you will get locked up worked for guns and I believe it will work for knives.

"Putting this legislation forward is an important step and I have made no secret that I support this move.

"I am proud that over the past three years we have seen a significant drop in knife crime.

"However, in recent months we have, in London, begun to see more young people being injured by knives.

"Anything that helps us all fight this is a good thing.

"I hope that this very clear message along with the targeted work of officers across London will help it become an increasingly rare crime and that fewer families will suffer the death or serious injury of a loved one."

Last year, 1,300 people received a non-custodial sentence or caution for a repeat offence of knife possession.

The former MP, who lost his seat in May to Labour's Joan Ryan, told the Enfield Independent: "The message should be loud and clear – we won’t tolerate carrying knives anymore.

"Let’s not forget, to kill someone with a knife you have to first carry a knife and I hope the true legacy of this law that both myself and David Burrowes secured is that it will save lives."

Earlier this year it was revealed by the Guardian there was, on average, one knife crime committed every day in Waltham Forest last year.   

Borough Commander Chief Superintendent Jackie Sebire said there was a 7.3 per cent reduction in knife crime in 2014.