The number of people caught carrying knives in England and Wales has risen to its highest level in six years, official figures show.
The courts dealt with more than 19,000 knife possession cases last year - the highest number since 2011.
The Ministry of Justice said the rise has been driven most recently "by increases amongst juvenile offenders".
A record 41% of adult offenders were jailed, while 11% of 10-17 year olds were sent to prison.
The MoJ said almost a third of juvenile offenders received a caution.
Justice Minister Sam Gyimah said: "Knife crime ruins lives and devastates communities, and those who carry blades should feel the full force of the law.
"These figures show that those convicted... are more likely than ever to go to prison, and for longer."
The average sentence for knife possession was between seven and eight months, two months longer than the average in 2008.
Some 34% of all sentences passed are for immediate custody, 23% are community sentences and 19% are suspended sentences.
A further 64% of adult repeat offenders received an immediate custodial sentence.
But shadow justice secretary Richard Burgon said: "Ministers promised 'two-strikes-and-you're-out' for knife possession, but a third of adult repeat offenders are still not being sent to prison."
The MoJ said sentencing decisions are a matter for independent judges.
About a quarter of the knife crimes took place in London, where offences have risen to their highest level for nine years.
It comes after London Trading Standards found that children as young as 13 are able to buy knives in London shops.
Using teenage volunteers to test if shops were complying with the law, London Trading Standards found that out of 724 test purchases, 96 retailers sold knives and blades to the volunteers.
It is illegal to sell knives to anyone under the age of 18.
As a result, 19 traders have been prosecuted while others received warnings and compliance advice.
London Trading Standards spokesman Steve Playle said: "Whilst it is commendable that 87% of shops refused to sell, it is concerning that children as young as 13 were actually sold knives."