New sentencing proposals will see 16 and 17-year-olds sent to jail for threatening people with knives or other weapons.
The introduction of the law could see up to 400, 16 and 17-year-olds jailed every year for wielding a knife, based on estimates from the Ministry of Justice.
Under the proposals, 16 and 17-year-olds convicted of using a knife or other weapon to threaten or endanger someone, would be sentenced to a four-month detention and a training order – the main custodial sentence for under-18s.
Half of the sentence would be served in custody, meaning the teenagers would spend at least two months in prison.
The Justice Secretary also plans to impose mandatory life sentences for anyone convicted for very serious sexual or violent crime for the second time.
Only those convicted of murder face a mandatory life term under current legislation in England and Wales
Speaking to the Commons Home Affairs Select Committee, Mr Clarke told MPs that judges find excuses not to apply mandatory sentences, saying that it was a “game that should not go on between the Parliament and the courts”.
The government recently announced proposals for a mandatory six-month sentence for adults convicted of this offence.
The debate over whether to extend the mandatory sentences to juveniles led to a reported row between Mr Clarke and Home Secretary Theresa May. Mr Clarke had seemed to disagree with Mrs May, when he urged caution before extending mandatory sentences to teenagers recently.
However when announcing the proposals, he said that a move was needed “to send out a clear message about the seriousness of juvenile knife crime”.