The UK has begun moving its most extremist prisoners, including those who have been involved in planning terrorism, to special cells dubbed "jihadi jails" to tackle growing radicalisation within the country's prison system.
The first such specialist centre has been set up at HMP Frankland near Durham in north-east England.
Two other centres, which are expected to be at HMP Full Sutton near York and at HMP Long Lartin in Worcestershire, are due to open in the coming months and the three centres together will hold up to 28 of the most subversive extremist prisoners.
"Any form of extremism must be defeated wherever it is found, and it is right that we separate those who pose the greatest risk in order to limit their influence over other prisoners," said UK's prison minister Sam Gyimah.
"These centres are a crucial part of our wider strategy to help tackle extremism in prisons and ensure the safety and security of both our prisons and the wider public," he said.
The mental health of the inmates being considered for referral to the units must be examined and each will have a care and management plan, and their placement will be reviewed every three months.
The UK's Ministry of Justice (MOJ) said those selected for separation in the specialist centres include those who have been involved in planning terrorism or are considered to pose a risk to national security.
Those seeking to influence others to commit terrorist crimes, or whose extremist views are purposely undermining good order and security in the prison estate, may also be sent to the centres.
The creation of the separate specialist units – dubbed jihadi jails or jails within jails – marks a break with the long-standing policy of dispersing convicted terrorist prisoners throughout the eight top security jails that make up the high security prison estate in England and Wales.
The decision to isolate the most dangerous subversives to prevent them from influencing others follows the Acheson review into Islamist extremism in prisons.
It had recommended such prisoners be removed from the general prison population and be given effective de- radicalisation interventions
Workers clean communication equipment aboard INS Surat on January 11