It came as Scotland Yard launched three separate murder investigations after fatal stabbings across the capital.Italian national Pietro Sanna, 23, was found with multiple stab wounds after a “brutal and vicious attack” in his own home in Canning Town at 11.40pm on Monday, police said.A man in his 30s also died after officers were called to reports of a stabbing in East Ham shortly after 8pm.Meanwhile, a 29-year-old man died after reports of a stabbing at a property in Islington at around 2am.Since the start of the year until June 18, 24 people under the age of 25 have been fatally stabbed in the capital. There have been nine murders in London in the last month. “The only way we can truly beat the scourge of knife crime on our streets is by properly funding youth services – the Government needs to step up, reverse these cuts and help provide the services we need to tackle knife crime.”Part of the mayor’s new plan would involve “naming and shaming” retailers who continue to illegally sell knives to underage customers.The police and Trading Standards will also do more “test purchasing”, to check online retailers are also abiding by knife sale rules.Pastor Lorraine Jones, whose son Dwayne Simpson was stabbed to death three years ago, joined Mr Khan at the initiative’s launch at the Dwaynamics boxing club in Brixton, south London.The club was started by her son Dwayne in 2013 as a boxing and fitness project to serve residents in the local Angell Town estate.She welcomed the mayor’s new measures, saying: “I know first hand the devastating impact knife crime has on a community and a family.”It is incredibly important that everyone works together to stamp knife crime out of our city once and for all.”Mr Khan said he backed the Met’s use of a “targeted, intelligence-led” version of the controversial stop and search policy. London Mayor Sadiq Khan has launched a major crackdown on the “scourge” after three fatal stabbings were reported in the capital within hours of each other.New measures will see schools given metal detecting “knife wands” and a new community sentence for those convicted of knife possession.He has also pledged an extra £625,000 to fund knife and gang crime projects in the city after the number of offences in London involving knives rose by 24 percent in 2016. Nationally, the figure was 11 per cent. “We need to send a strong signal that carrying and using knives is totally and utterly unacceptable. Mr Khan said: “Every death on the streets of London is an utter tragedy, and I am deeply concerned about the rise in knife crime on London’s streets. Dozens of families have been bereaved; many more have seen their loved ones severely injured. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. More than 500 knives, 11 firearms and 50 offensive weapons that have been recovered during an Operation Sceptre week of actionCredit:METROPOLITAN POLICE He told the Press Association: “What I’m not in favour of is an indiscriminate use of stop and search, or stop and search being used on industrial scales.” He said the practice would be used to “get rid of the dangerous weapons” and “dangerous people” from the streets of London.The latest bid to tackle knife crime in London comes just a week after the Met said they would arm hundreds more officers with Tasers, bringing the total carrying the weapon to more than 6,400 in the capital.As well as gang-related knife crime, a number of recent high profile attacks, including the murder of Jo Cox, and the Westminster and London Bridge terrorist attacks, have all involved knives.The Met said they had recovered more than 500 knives from the streets of London during an intense “week of action” to tackle knife crime between June 19 and June 27.Officers working on the Met’s Operation Sceptre also seized 11 firearms, and made 622 arrests, including 180 for possession of a knife or offensive weapon.In Hackney, a member of the public alerted police to a suspicious vehicle which was later found to contain a samurai sword, machete, a “Rambo-style” knife, as well as cash and cannabis.Acting Detective Chief Superintendent Sean Yates said: “We are starting to see a mobilisation from the community against knife crime and we need this to continue. Mayor of London Sadiq Khan and Met Police Commissioner Cressida DickCredit:Lauren Hurley/PA Wire “It is those individuals who will have the biggest impact on getting the message out there to young people that it is not acceptable to carry a knife.” “We need to change attitudes to carrying knives and are encouraging key people in positions of influence to drive this messaging forward.