The government's Prevent strategy is targeting pupils who are "nowhere near being drawn into terrorism" and risks violating their human rights, according to a new report.
It warns that teachers may be "over-reacting" to signs that pupils could become radicalised, leading to children as young as four being "targeted", as a result of the government's controversial counter-terrorism strategy.
The Open Society Justice Initiative, which published the research, is calling for the government to repeal the statutory duty on teachers and health professionals to "have due regard to the need to prevent people from being drawn into terrorism".
Eroding Trust: The UK’s Prevent Counter-Extremism Strategy in Health and Education concluded that the strategy could be counter-productive.
Its "erroneous targeting of individuals who are nowhere near being drawn into terrorism may make them more susceptible to that path", it said.
Official guidance says teaching staff must be able to identify children who may be vulnerable to radicalisation, and take action where they observe concerning behaviour.
This could involve referring children to a "Channel" programme, aimed at providing support at an early stage to those who may be vulnerable to being drawn into terrorism.
However, the guidance does not specify that teachers referring children to these programmes must comply with safeguarding obligations, the justice initiative stated in its report..
It said: "There are serious concerns about the treatment of children under Prevent.
"Although the government describes Prevent as a form of 'safeguarding'... the two sets of obligations have materially different aims, particularly with respect to children.
"In contrast to the Prevent strategy, for which the primary objective is preventing terrorism, the primary objective of the duty to safeguard children under domestic legislation is the welfare of the child."
At one Channel event highlighted in the report, children were asked whether they agreed or disagreed with statements such as: “The UK is a good place to live for me and my family”.
They were told their answers would be anonymous, but were then asked to write their names on the paper - a potential violation of their rights to privacy, according to the report.
In another case, a nine-year-old Muslim boy was questioned by his headteacher after a joke he had made about using "bombs and guns" to get the school prom was taken out of context.
In a well-reported incident, a four-year-old boy was referred to "Channel" by his nursery after drawing a picture of a cucumber. The nursery manager told the boy's mother that he had said it was a "cooker bomb".
The Prevent training that one teacher received in the West Midlands provided a indicators of “radicalisation” to watch out for, including whether the child had a different group of friends, had strong political beliefs, changed the way they dressed, or if there was a drop in grades.
The report said: "These indicators could potentially apply to a broad swath of children who have nothing to do with terrorism while running the risk of penalising them for their political views and violating their right to freedom of expression.
"Many young people go through a period when they change their dress, when they take strong political stands, when they may be angry at authority."
Some teachers told the researchers they did not find the strategy helpful. An assistant head teacher at a London primary school called the Prevent training she attended in January 2016 "a tick-box exercise”. She did not think “a single person knows what to look for, how to identify signs of radicalisation”.
In July, Parliament's joint committee on human rights called for an independent review of the Prevent strategy. This came after TES revealed in March that the number of people referred by education institutions to Prevent had exceeded the number of tip-offs from the police.
The Home Office has been contacted for comment.