One of Britain's most high-profile Muslim lawyers has accused established Islamic groups of peddling "myths" about the Government's main anti-extremism policy.
Nazir Afzal backed the controversial Prevent programme, saying it had stopped people including children travelling to Syria, in an interview with the Times.
Mr Afzal, who quit as chief executive of the Association of Police and Crime Commissioners (APCC) following the Manchester terror attack, also criticised the Muslim Council of Britain, saying it was "reluctant" to stand up for British values and the rule of law.
He told the paper: "It (Prevent) has stopped at least 150 people from going to Syria, 50 of them children.
"It's grassroots - it's not about criminalising and it has an impact but it's constantly undermined by myths that urgently need to be challenged."
The Prevent programme aims to intervene early and provide support for those deemed to be at risk of being drawn into violent extremism.
There were around 7,500 referrals to the initiative in 2015/16.
Mr Afzal, who was previously the chief crown prosecutor in the North West, appeared on the BBC's Question Time programme in the wake of the deadly attack on the Ariana Grande concert at Manchester Arena on May 22.
It later emerged that he had resigned after being told it would be inappropriate for him to appear because of the potentially controversial policing issues that could have been raised.
In his interview with the Times he criticised the MCB, saying that at its annual general meeting last year there was "nothing about radicalisation and nothing about the threat of people going to Syria".
He added: "We all have a responsibility to stand up for British values and the rule of law. They always come to the party reluctantly, rather than routinely doing so because it's the right thing."
The MCB has been critical of the methods used by Prevent.
In October, announcing it would set up its own counter-extremism scheme, it said: "Having Muslims pass through subjective and discriminatory counter-extremism litmus tests as a condition of engagement only reinforces the terrorist narrative.
"The Prevent strategy exacerbates this problem and it is quite clear that it does not currently have the support of many among Muslim communities across the UK, yet the threat of terrorism is real and severe."