Britain’s most dangerous Islamists will be housed in a special unit to stop them converting their fellow inmates.

The Times reports work is currently under way at HMP Frankland near Durham, which will have a “prison within a prison” to keep Islamic extremists away from other prisoners.

The prison has already been home to some of Britain’s most notorious terrorists including Tanvir Hussain, who tried to use liquid bottles to blow up flights from Heathrow to the United States, and Dhiren Barot, who was behind a plot to detonate a radioactive “dirty bomb” in Britain.

Michael Adebolajo, who murdered soldier Lee Rigby on the streets of London, was also transferred to the prison after fears he was radicalising inmates at HMP Belmarsh.

The plans follow a report by former prison governor Ian Acheson, who recommended that some extremists who present a “particular and enduring risk to national security through subversive behaviour, beliefs and activities” should be removed from the general prison population.

A spokesperson for the Ministry of Justice said: “Islamist extremism is a danger to society and a threat to public safety – it must be defeated wherever it is found. We are committed to confronting and countering the spread of this poisonous ideology behind bars.

“Preventing the most dangerous extremists from radicalising other prisoners is essential to the safe running of our prisons and fundamental to public protection.”

In December 2015, the former chief inspector of prisons warned Islamic extremists were using British jails to recruit inmates as potential terrorists.

“There are undoubtedly a small number of very dangerous men motivated by a religion or ideology who are trying to recruit other people so they will go on to commit offences linked to that ideology or religion,” Nick Hardwick said.

“You do have Muslim gangs but the point about it is, it is a gang.

“That is more important than it is Muslim. There might be pressure to join up, but how real that conversion is is the big question.”