Referrals to a government deradicalisation programme increased sharply in the first year after a new counter-extremism duty was imposed on public bodies, new figures show.
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 figure represented a 75% rise on the previous year, when there were 2,632 referrals, data released by the National Police Chiefs' Council shows.
From July 1 last year, authorities including councils and schools were placed under a statutory requirement to prevent people from being drawn into terrorism.
Channel, which is part of the controversial Prevent strategy, provides support to individuals who are identified as vulnerable to being drawn into extremism.
In the year to June 2016, there were 2,311 referrals relating to under-18s - an increase of 83% on the previous year.
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.
Jonathan Russell, head of policy at counter-extremism think tank Quilliam, said: "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."
Mr Russell added that the increase in referrals could be partly attributed to the "increased visibility" of the so-called Islamic State.
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."