The Prevent anti-extremism strategy is "absolutely fundamental" to Britain's counter-terrorism efforts, a police chief has said.
Simon Cole highlighted the role played by the scheme in helping to stop people travelling to fight in Syria and "stabilising" communities amid a heightened threat from the extreme far-right.
He argued that Prevent is often presented in "hysterical" terms, which contrasts with the reality of a process aimed at supporting often vulnerable individuals.
The latest figures show that in 2015/16 there were around 7,500 referrals to Prevent - a rate of 20 a day.
It has been credited with playing a role in disrupting more than 150 attempted journeys to the conflicts in Iraq and Syria, and is also handling a growing number of cases linked to far-right extremism.
But it has repeatedly come under fire, with critics labelling it heavy-handed and "toxic", and there have been calls for it to be independently reviewed.
Mr Cole, the National Police Chiefs' Council lead for Prevent, defended the programme in an interview with the Press Association.
He said: "Some of those that criticise, criticise perceptions of Prevent rather than what it is.
"Something that gets lost in the debate is that this is a voluntary scheme which takes place in the pre-criminal space.
"This is not about people who are suspected of terrorist offences. This is about people who professionals, friends, family, community members have concerns about and who need some help and support."
Mr Cole, chief constable of Leicestershire Police, emphasised the importance of a combination of education and enforcement for policing issues.
"We try and divert, allow people the opportunity to help them make better decisions," he said. "It's absolutely fundamental."
He said he believed it is "really likely" people have been deterred from going on to commit terrorist offences following interventions from Prevent.
"It's really hard to empirically demonstrate that," he said. "Certainly there are people who have intended to go and travel and fight, there are people who may have carried out right-wing acts of extremism.
"It has enabled us to try and help stabilise communities and stop people getting us into a cycle of aggravation."
He acknowledged that some communities are "very suspicious" of Prevent and stressed the importance of being as transparent as possible about a programme which has drawn accusations of secrecy.
Summarising the typical process, he said: "There's an assessment about an individual and a programme of support put round them.
"Sometimes that programme is nothing to do with extremism or radicalisation. It's identifying that somebody might need job opportunities, educational opportunities, that their housing provision isn't great."
He said the assessment process following a referral is "very mature", "thoughtful" and "well-motivated".
Mr Cole added: "And that gets lost in all the noise. It's a group of professionals trying to identify how somebody can be supported.
"It's sometimes presented in quite hysterical terms as part of a sort of spying operation. Actually it isn't that. It's quite mundane almost."
:: Warned that the internet enables young people to access information in an "uncontrolled" way, adding: "Lots of that's good, but some of it is a threat";
:: Said Daesh - also known as Islamic State - has a "really sophisticated" communications operation;
:: Estimated that just under 10% of referrals were from families and communities, saying: "We would like that to be more. It's a big step to refer somebody you love into a formal process around safeguarding. We understand that, we have huge sympathy";
:: Described a new counter-terrorism duty imposed on state bodies last year as "sensible" - but it has proved to be "quite challenging in some environments where people see it as spying and intruding and preventing access to a space for thought";
:: Denied that a referral that goes nowhere should be seen as a failure, saying: "I'd be really worried if every single referral led to an action."
Prevent was introduced following the 7/7 attacks in London as part of a wider counter-terrorism strategy known as Contest.
Last year the Prevent duty was introduced, requiring organisations such as schools and local authorities to "have due regard to the need to prevent people from being drawn into terrorism".