About 2,000 of those referred to the Prevent programme were under 15

A nine-year-old boy was referred to a government anti-terrorism scheme after he stood up in class and declared his support for Isis, the Home Office disclosed yesterday.

The boy was among 2,000 children aged under 15, including more than 500 girls, identified as potential extremists. He said that he had searched online for videos of beheadings and people being burnt to death by Isis after the Paris terrorist attacks two years ago.

After a year of specialist support, including work with his school, where he was being bullied, he was diverted away from extremism, the Home Office said.

Experts said that children as young as five had been sent for help because of siblings’ involvement in terrorism.

The government has published for the first time