Automatic jail sentences will be introduced for 16 and 17-year-olds who commit knife crimes in a sweeping law and order package announced last night by Kenneth Clarke, the Justice Secretary.
Adults guilty of two serious violent or sexual attacks will face mandatory life terms, while homeowners will be given enhanced legal rights to defend themselves against burglars.
The moves represent a defeat for Mr Clarke's determination to take a more liberal approach to sentencing.
It is understood the final shape of the proposals, certain to push up the prison population, were settled yesterday after David Cameron's intervention.
Only 24 hours earlier Mr Clarke had opposed calls to include under-18s in plans for automatic jail terms for knife crime – a punishment backed by Theresa May, the Home Secretary, and many Tory MPs.
He had argued that the move ran counter to the historic British way of dealing with juvenile offenders.
But last night he disclosed he had lost the Cabinet battle and would be legislating for mandatory minimum four-month terms for youths aged 16 and 17 for "aggravated" knife offences.
Adults will receive an automatic six-month sentence for the same crime.
Mr Clarke also announced that for the first time, mandatory life sentences would be introduced for crimes other than murder. Ministers will bring in a US-style "two strikes and you're out" policy, in which commiting a second serious sexual or violent offence – including terrorism, child sex offences and "causing or allowing the death of a child" – will carry a life sentence.
Earlier this week, Mr Clarke told MPs that the current "three strikes and you're out" policy, which should see anyone convicted of three offences jailed, was widely ignored by judges.
The law will also be amended to make clear householders are under no duty to retreat from an attacker when acting in self-defence and can use reasonable force to defend themselves and their property. It follows several cases in which suspected intruders have been killed.
The Government will scrap the Imprisonment for Public Protection (IPP) sentences, brought in by Labour in 2005, under which serious offenders are freed only if they satisfy the Parole Board they are safe to be released.
The Government has described IPPs as inconsistent and incoherent.
They will be replaced by an Extended Determinate Sentence requiring that serious offenders serve at least two thirds of their prison terms.
Mr Clarke said the moves would restore "clarity, coherence and common sense to sentencing".