Ken Clarke has climbed down on opposition to compulsory prison sentences for under-18s who use knives.
The Ministry of Justice has announced new mandatory sentences for those who carry knives, including 16 and 17 year olds - two days after the justice secretary said it would be a "bit of a leap" for Britain's judical system.
On Tuesday, Ken Clarke voiced opposition to the plans, telling the home affairs select committee: "We have, because of the seriousness that we attach to knife crime and we think a strong message has got to be sent to people indulging in knife crime - have agreed such a mandatory sentence for adults.
"This is being tabled and the government's proposal. The idea that mandatory sentences for certain types of offence, to young offenders, to children, to juveniles is a bit of a leap for the British judicial system."
Estimates show up to 400 teenagers could be jailed every year under the plans.
Anyone who commits a second serious sexual or violent crime will also receive a mandatory life sentence.
In a statement released on Wednesday Ken Clarke said: "The new regime will restore clarity, coherence and common sense to sentencing, rid us of the inconsistent and confusing IPP regime and give victims a clearer understanding of how long offenders will actually serve in prison.
"We have already announced that we are bringing in an automatic prison sentence for any adults who use a knife to threaten and endanger. Clearly any extension of this sentence to children requires very careful consideration. However, we need to send out a clear message about the seriousness of juvenile knife crime, so we are proposing to extend a suitable equivalent sentence to 16-17 year olds, but not to younger children."
Labour's Sadiq Khan said he welcomed the news: “A clear message needs to be sent that knife crime terrorising people on our streets is unacceptable and will be punished.
“However, this Government’s plans are undermined by the fact that they are limiting the ability of the police to catch criminals in the first place by cutting front line police services.”