Knife crime has surged to a seven-year high amid police fears of an epidemic of violence on the streets.

And use of blades among children has rocketed to its highest level this decade.

Courts dealt with more than 21,101 knife cases last year – the highest number since 2010 – according to official figures.

It is equivalent to one attack every 25 minutes and a 5 per cent increase on 2016.

Justice minister Rory Stewart (pictured) said: ‘Knife crime is horrifying, it causes catastrophic damage to families with tragic consequences'

Meanwhile, the number of those aged between ten and 17 cautioned or sentenced after being caught with blades hit 4,479 in the year to June – more than at any time since 2009.

Knives and other sharp weapons have killed at least 64 people in London alone this year.

Justice minister Rory Stewart said: ‘Knife crime is horrifying, it causes catastrophic damage to families with tragic consequences. We need sentences that punish anyone who commits knife crime and deters anyone from doing it in the future.’

Police have been shocked by the increasingly ‘frenzied’ nature of attacks, with many victims stabbed repeatedly, sometimes by mobs of attackers linked to gangs.

The extent of the attacks has prompted calls for greater use of police stop and search tactics, a crackdown on social media websites that promote gang violence and a halt to cuts to neighbourhood police officers.

Figures also reveal that 37 per cent of offenders with at least one previous conviction for knife possession were not sent to prison. That was despite the Government introducing a ‘two strikes and you’re out’ minimum six-month sentence in 2015.

The latest statistics, published by the Ministry of Justice, revealed that 1,724 of 4,669 repeat knife offenders were spared immediate custody, meaning they were freed to pose a risk to the public.

Some 36 per cent of offenders were jailed immediately, while 11 per cent received a caution – the lowest ever proportion. The average sentence for knife possession was nearly eight months – a month longer than the previous year.

Campaigners say websites such as YouTube, owned by Google, should do more to pull down videos promoting violence and knife crime. Ministers have unveiled plans for a package of measures following a surge in violent offences recorded by police.

The proposals include a drive to tighten the regime covering online sales of knives following concerns that age-verification checks can be sidestepped.

Where a knife is sold on the internet, it will be an offence to deliver it to a private residential address. The buyer would have to collect the knife in person at a location where their age can be checked.

Police say the availability of smartphones has also created an almost unlimited opportunity for gangs to antagonise each other.

Their taunts can be viewed by a much larger audience for a much longer time, sparking cycles of tit-for-tat attacks.

Last month the Government announced it would spend nearly £24million to steer young people away from crime as part of its Serious Violence Strategy.

Justice Minister Mr Stewart added: ‘These figures show we are catching and prosecuting more of those carrying a blade, and we are sending them to prison for longer.’