A sharp jump in referrals to a government deradicalisation programme was recorded in the first year after a new counter-extremism duty was imposed on public bodies.
A total of 4,611 people, including more than 2,000 children and teenagers, were earmarked for possible intervention by the Channel scheme from the start of July 2015 to the end of June 2016 - equivalent to 12 a day.
The tally was a 75% rise on the previous year, when there were 2,632 referrals, figures obtained by the Press Association show.
From July 1 last year authorities including councils and schools were placed under a statutory requirement, known as the Prevent duty, to stop people being drawn into terrorism.
As well as growing awareness of the duty, officials believe the rise in referrals may also reflect a response to world events such as the Paris attacks in November.
In the year to June 2016 there were 2,311 referrals relating to under-18s - an increase of 83% on the previous year - with 352 of the children aged nine or under, 989 aged between 10 and 14 and 970 aged between 15 and 17.
In the 12 months after the duty took effect referrals from schools climbed to 1,121, more than double the 537 in the previous year, statistics released by the National Police Chiefs' Council following a Freedom of Information request reveal.
Channel, which is part of the controversial Prevent strategy, provides support to individuals who are identified as vulnerable to being drawn into terrorism.
It is aimed at all forms of potential extremism. In 2015 around 70% of referrals were linked to Islamist-related extremism and roughly 15% to far-right extremism, according to a government report published in July.
Jonathan Russell, head of policy at counter-extremism think tank Quilliam, said factors behind the rise in referrals could include the "increased visibility" of so-called Islamic State leading to more radicalisation and the statutory Prevent duty resulting in more referrals because frontline workers can now "spot the signs".
Another possibility was that referral is seen as the safest option "in the absence of full training about the range of prevention measures", he said.
Mr Russell added: "The important thing to note is that the stats show that trained professionals think an increasing number of young people are vulnerable to radicalisation.
"We therefore need to support Prevent which aims to safeguard them, work with teachers to ensure they have the requisite resources and training, and engage with civil society-led initiatives."
Russell Hobby, general secretary of school leaders' union NAHT, said:"Prevent has raised awareness of the dangers of radicalisation of young people, and this has naturally led to an increase in the number of those referred to the Channel programme.
"We need to ensure that training for teachers and school leaders is provided to make sure that they are able to fulfil their duties and to ensure that referrals are appropriate.
"What is of more interest is the outcome of those referrals. Only by looking at that will we know how effective the system is."
Engagement with Channel is voluntary and it is not a criminal sanction. Not all referrals are ultimately deemed to require intervention.
The Home Office said more than 1,000 people have been successfully provided with support through Channel since 2012.
A spokesman said: "We have a duty to challenge, at every turn, the twisted narrative that has exploited some of our vulnerable young people.
"Many referrals to the programme require no further action, some are referred to other services for support, while for others receiving support through Channel is the right option.
"Like safeguarding mechanisms for other risks such as child sexual exploitation, vulnerable children deserve to have the support they need.
"We will continue to work in partnership with communities of all backgrounds to challenge those who spread hatred and intolerance."