Efforts to combat a surge in knife crime are being undermined by inconsistent and lenient court sentences, according to the Police Federation and anti-knife crime campaigners.
Latest figures show that two-thirds of those carrying a knife escape a custodial sentence and one-in-five repeat offenders are still avoiding prison, despite the government introducing a "two-strikes and you're out" policy for those caught with a knife on more than one occasion.
John Apter, chairman of the Police Federation, the body representing rank-and-file police officers, said a tougher approach to sentencing was urgently needed.
"For far too long, we've been soft on those who carry knives and those who inflict injuries with knives," he said.
"We need to step up our game as a country and demonstrate that carrying a knife is completely unacceptable.
"That's where the law must step in and there must be a consequence.
"There's got to be a consequence, because without that consequence, this epidemic in knife crime will continue and these kids will keep getting murdered on our streets."
Emma Caley-Taylor now campaigns for tougher sentences after her son Jordan Taylor was killed by another man armed with a knife in Trowbridge, Wiltshire.
A trial jury believed his killer, Hayden Maslen, who said he acted in self-defence and – despite admitting carrying a deadly weapon – he served just 10 months in prison.
Jordan's mother said the sentence was an outrage.
She told Sky News: "It was absolutely devastating, we were in bits. We couldn't believe it.
"It's given out the wrong message. Knife carriers, they talk amongst each other.
"They're criminals, not all, but the majority are.
"I personally think they need to be set an example, there needs to be punishment, there needs to be a deterrent. At the moment, there's nothing.
"We're seeing it time and time again.
"People that use a knife get a suspended sentence, people that carry a knife get cautions.
"What we're saying is that it's not that serious at all, it's fine to go out with a knife, because nothing will happen to you."
Just last month, Joshua Gardener, 18, escaped a jail term despite a shocking attack on a motorist in south London.
Another motorist recorded mobile phone footage showing the teenager with a large knife, repeatedly striking at the windows of the car in Croydon.
That sentence is now being reviewed by the attorney general, who is due to rule later this month on whether it was too lenient.
In a rare interview, the chairman of the Sentencing Council told Sky News that although judges are aided by sentencing guidelines, they had to be able to judge each case on its merits.
Lord Justice Holroyde said: "I do of course understand, as all judges and magistrates do, the impact of knife crime on the victims, their families and the public."
The Court of Appeal judge said he could not comment on specific cases, but that judges "should follow the guidelines, unless it would be contrary to the interests of justice to do so in a particular case".
"I appreciate there may be concerns that sentences appear to be inconsistent or too low, but what has to be remembered is that every case is different," he said.
"The judge has to make a balanced decision and so has to take account of all the relevant factors relating to the particular individual offence, including the harm, or potential harm and including any other relevant feature which makes the case either more serious or less serious."
In the year to September, more than 21,300 knife and offensive weapon offences were dealt with by the criminal justice system in England and Wales, including around 4,500 committed by children.
The majority were handed a community sentence by courts, such as unpaid work, but 558 were jailed and 1,300 were given formal warnings and cautions.
Mr Apter said: "I believe strongly in rehabilitation of offenders, people should have chances.
"But there are some people who just need to be locked up, they need to be punished, there needs to be a consequence for their action.
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"We hear all too often about these offenders, who dress up in a suit for their annual court appearance, they stand in front of a magistrate or a judge and they're given a slap on the wrist.
"As they turn around, they're laughing, literally they are laughing, they are taking advantage of a soft system and it's a disgrace, it's letting down the public and it's letting down the victims."