Young people who commit violence offences should be banned from using social media such as YouTube, Snapchat and Instagram, according to the chair of the all-party parliamentary group on knife crime.

Speaking before the launch of the government’s new serious violence strategy, the MP Sarah Jones urged the extension of criminal behaviour orders (CBOs) to give courts the power to ban individuals from using social media.

Senior officers are concerned that online content on YouTube and other sites is helping fuel the current knife crime and gun epidemic – last month was the bloodiest in London for nearly a decade. Yet tech companies are refusing to remove some content despite requests from the police.

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On Sunday the Home Office will move to tighten up other online loopholes by announcing tough restrictions on knives bought through the internet. The new offensive weapons bill, which will be published within weeks, aims to prevent knives that are bought online being sent to residential addresses, as well as making it illegal to possess certain offensive weapons, such as “zombie” knives and knuckledusters.

The home secretary, Amber Rudd, will tomorrow unveil the serious violence strategy to combat a rising toll that includes more than 50 people murdered in London so far this year. It will place renewed emphasis on early intervention and prevention, along with increased support for community groups working with young people, a package of measures that confirm the Home Office’s acceptance that the killings cannot be halted through increased convictions and tougher sentencing.

“It’s about stopping people before they become involved in gangs, before they pick up a knife, and if they have become involved in such activity, stopping them before they get any further,” said a Home Office source.

The strategy also contains measures to tackle so-called “county lines” drug trading, where urban gangs force children as young as 12 to traffic drugs in suburban or rural areas using dedicated mobile phones, along with fresh demands for social media companies to take action against video sites that glorify violence.

Jones hopes that the Home Office will back the broader use of CBOs, which replaced Asbos in 2014, and revealed that Rudd had described their potential effectiveness in tackling youth violence as “compelling”.

“We know the causes of knife crime and violence are multiple, but one factor impacting the scale of the problem is social media, because it is fuelling a cycle of violence,” Jones said.

Meanwhile, a number of senior parliamentary figures are calling on Rudd to incorporate an “ambitious target” to halve deaths from serious youth violence over the next decade as part of her strategy. A letter, signed by 11 chairs and commissioners from cross-party campaign groups, and David Blunkett, the former home secretary, urges the government to “put children and young people at [the] heart” of the strategy and treat the epidemic of violence as a “public health” issue.

It states: “Knife crime is an epidemic, spreading through our communities and we know that violence breeds violence.

“A truly new and multi-agency approach will recognise this as a public health crisis, tackling the problem at source while immunising future generations against violence.”

More immediate actions were evident on Saturday with an extra 300 Metropolitan Police officers deployed in the areas of London worst affected by a spate of violent crime.

Sunday’s Home Office announcement of new legislation also includes measures to make prosecutions easier by changing the legal definition for threatening someone with an offensive weapon and banning the possession of a knife on a further education premises, following data that shows knife-carrying in schools has soared by 42% over the last two years.