Britain's most notorious hate preacher, Anjem Choudary, has been moved to an isolation unit created for prisoners who pose a serious threat to national security while behind bars.

Choudary was jailed for five-and-a-half years in September for encouraging British Muslims to support the terrorist group Isis.

The cleric has been moved to a "separation centre" at HMP Frankland, a high-security prison in County Durham, The Sunday Times revealed on 23 July.

He was reportedly moved to the centre after he refused to stop preaching his extremist views to other inmates despite repeated warnings from prison staff.

Michael Adebolajo, the killer of Fusilier Lee Rigby, as well as serial killer Levi Bellfield and child killer Ian Huntley are serving sentences at HMP Frankland.

Frankland's separation centre is one of three high security units in the country. The other two are Woodhill in Milton Keynes and Full Sutton in Yorkshire.

Ian Acheson, who led the government review into Islamic extremism in UK prisons, said separating "subversive hate preachers from their audience is a necessary step to prevent the spread of Islamist extremism".

"The possibility of hope and change is important, not just as a moral abstraction but because it will keep staff and prisoners safer," he added.

The government launched a new task force to tackle radicalisation in prisons earlier this year. A strategy centre was opened in London in April and specialist teams have been placed in different parts of the country to "combat and defeat terrorist threats posed by prisoners."

At the time of the launch, prisons minister Sam Gyimah said: "By countering the poisonous and repugnant activities of extremists, we will help ensure the safe running of our prisons and keep the public safe."