"The recommendation was welcomed by Professor Ian Acheson, a senior adviser to the Counter-Extremism Project and a former prisoner governor.

'It’s the idea that everyone can be redeemed that is infecting the approach, which is always looking for improvement and for reduction of risk,' he said.

'It means officials are particularly vulnerable to psychologically sophisticated, ideologically-motivated terrorists. The terrorists don’t have to be particularly intelligent, they just have to be cunning and adept at hiding their true motivations.'"