Emergency legislation to prevent the automatic release of terrorist prisoners has become law – two days before the latest extremist offender was due for release.
The government rushed the Terrorist Offenders (Restriction of Early Release) Bill through parliament, after two former terrorist prisoners went on to launch attacks in London within two months of each other.
The change will affect around 50 prisoners, due for automatic release halfway through their sentences, making sure they now serve at least two-thirds of their prison term before they are considered eligible for release.
Before being freed, they will now also need to pass a review by a panel of specialist judges and psychiatrists at the Parole Board.
Sunderland shopkeeper Mohammed Zahir Khan, who was jailed for four-and-a-half years in May 2018, was due for release on 28 February.
He was arrested after posting extremist material online calling for a "year of fear" and pledging support for the terror group ISIS.
The change in legislation will allow authorities to keep him in prison for another year, before he is considered for parole.
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The emergency legislation was drawn up in the wake of the Streatham attack in south London, earlier this month.
Former terror prisoner Sudesh Amman, 20, stabbed two members of the public on Streatham High Road, just 10 days after he was automatically released from jail.
He was jailed in December 2018 for possessing and distributing terrorist documents but had been freed automatically, midway through his sentence.
Just two months earlier, another convicted terrorist, Usman Khan stabbed and killed two people at a prisoner rehabilitation event near London Bridge.
Introducing the sentencing bill earlier this month, the Justice Secretary Robert Buckland QC MP said: "No dangerous terrorist should be released automatically, only to go on and kill and maim innocent people on our streets.
"Enough is enough. The government will do whatever it takes to keep the public safe, including making sure no terror offender is released early without a through risk assessment by the Parole Board."
After the Streatham attack, the prime minister expressed an apparent lack of faith in deradicalisation programmes, claiming the "instances of success are really very few".
That places a renewed emphasis on the police and security services to try to manage terrorist offenders on their release.
One of the country's most senior police officers, West Midlands Chief Constable Dave Thompson, said the management of terror offenders and other extremists posed a significant challenge, but authorities have sophisticated systems in place.
"This is a huge challenge that has been brought into focus," he said.
"To a degree we are in this position because of one of the successes of policing and the security services in putting a lot of people into the prison system, who are now coming out.
"Here in the West Midlands we have a dedicated team that polices prisoners who have been released to make sure that they are adhering to the conditions of their release.