Lord Carlile of Berriew, a former independent reviewer of terrorism legislation who helped lay the groundwork for the review, said: “They should remove Prevent functions from local authorities and make it a more independent service.

“Prevent co-ordinators should no longer have a relationship with local authorities because they are subject to external pressures that have nothing to do with Prevent like resources and policy.

“The Home Office should retain control of Prevent. They should set policy and provide the money. It should then be devolved down to a regional structure that could mirror the way the 11 regional counter-terrorism units are organised. Being able to relate to those counter-terrorism units and raise issues with them would be very valuable.”

The review is also expected to recommend that the Channel panels, responsible for overseeing deradicalisation schemes for those most at risk, are too big, often with up to 20 people. They could be slimmed down to five.

Some insiders are also concerned that the increasing focus on Right-wing terrorism should not be at the expense of Islamist extremism, which still poses the biggest threat.

One insider said: “Whilst in numerical terms Right-wing extremists have grown exponentially, Islamist extremism continues in ways exemplified by yesterday’s case [of Sir David Amess’s murder]. These are the most dangerous terrorists and ones in which sheer numbers don’t tell you the story.” 

‘I’d nod my head and they would leave me alone’

Ali was on Monday found guilty of murdering Sir David during a constituency meeting in Oct 2021.

The killer, who targeted Sir David because he voted to bomb Islamic State in Syria, was referred to Prevent in 2014 and boasted in his trial about how he easily managed to appear compliant when forced to engage with the authorities.

“I just knew to nod my head and say ‘yes’ and they would leave me alone afterwards, and they did,” he told the court last week.

A Home Office spokesman said: “Prevent remains a vital tool for early intervention and safeguarding. We will not allow extremists or terrorists to spread hate or sow division and Prevent remains an important driver to help divert people away from harm.

“The Independent Review of Prevent, led by William Shawcross, will ensure we continue to improve our response and better protect people from being drawn into poisonous and dangerous ideologies. We will consider its findings and recommendations carefully once it is completed.”