London police have launched their fifth murder investigation in a week, after a 16-year-old boy died in a suspected stabbing, and extra officers were taken off leave and deployed to the streets.

Police were called to “reports of a shooting” in Tulse Hill, south London, on Monday night with the youth pronounced dead just before midnight. Officers said, “it is believed the boy’s injuries are stab rather than gunshot wounds.”

Earlier in the day, a 17-year-old and 18-year-old were arrested on suspicion of murder following the killing of Malcolm Mide-Madariola, also 17, outside a busy Tube station on Friday afternoon.

Hours before on Friday, a 15-year-old boy was killed just yards from his home in Lewisham, south London, and a 16-year-old was stabbed on New Kent Road in Southwark.

Following the wave of violence, Sky News reports that hundreds of extra police officers – many of whom will have been taken off leave – will be on the beat to protect the public.

Metropolitan Police Commander Stuart Cundy said the deployment followed a “terrible” few days in the capital, which brought the number of murders in the capital to 119 so far this year.

The desperate move came as London Mayor Sadiq Khan said it could take a generation to get a grip on knife crime in the city.

London Mayor @SadiqKhan says "it's more difficult" to solve knife crime because of budget cuts but "there are other complex reasons as well" #r4today — BBC Radio 4 Today (@BBCr4today) November 5, 2018

Mr Khan told BBC Radio 4: “It will take some time. I know that because of the lessons we’ve learnt from places like Glasgow, where it took them some time to turn this round. To really make significant progress can take up to ten years, a generation.”

Former UKIP leader Nigel Farage hit back at Mr Khan for “appearing blasé” in his response to the crime wave, suggesting the Mayor brings back “tougher” measures.

Speaking on his LBC radio show, he blasted: “I just don’t think it’s good enough, I think he’s copping out.

“We’ve just got to get tough. Metal detectors in schools, bringing back stop and search, and real penalties for people who are caught with knives.

“That may not solve all of the social problems that have been leading to this but goodness me, it might just make our streets a bit safer in the short term.

“He appears almost blasé in his response to the rise in knife crime in London, and I think people want to see a bit more leadership and a bit more action. That is my view.”

He added: “Look I’m not blaming him for all of this – when he became Mayor of London we already had a problem, but it has exploded over the course of the last year or two.

“I just don’t think he’s talking about this with enough sense of urgency.

“There are things that can be done and just to blame police cuts on its own simply isn’t enough.”