'Two strikes' life sentences plan for serious sex and violent crimes
People who commit "the most serious" violent or sexual crimes more than once will face automatic life sentences, Chris Grayling has warned.
The justice secretary told the Tory conference that those given two prison terms lasting more than 10 years would be upgraded to the greater punishment.
The "two strikes and you're out" threat would act as a deterrent, he said.
The powers are contained in the Legal Aid, Sentencing and Punishment of Offenders Act 2012.
Mr Grayling became justice secretary last month, taking over from Ken Clarke in Prime Minister David Cameron's government reshuffle.
Outlining the sentencing change, he said: "It's called 'two strikes and you're out'. So, if you commit two serious violent or sexual offences, you will get an automatic life sentence.
"Everyone deserves a second chance. But those who commit the most serious offences, crimes that would attract a sentence of 10 or more years, cannot be allowed to just go on and on causing harm, distress and injury.
"Those people are a real threat to our society, and we must treat them as such."
He added: "We are also legislating to use more state-of-the-art technology to enforce curfews and exclusion zones.
"So, for example, we'd be far better placed to know whether a paedophile has broken his order by hanging around."