A teaching union in Bradford has warned that it will blow the whistle on any head teachers it suspects are illegally excluding troublesome pupils after a national inquiry called for hefty fines to be imposed on offending schools.

The children’s commissioner for England, Dr Maggie Atkinson, conducted a two-year inquiry into illegal exclusions, which found that many schools were excluding youngsters by placing them on extended study leave, on part-time timetables, coercing them to leave or face permanent exclusion or removing them from the school for having the wrong haircut.

Illegal exclusions are defined as those that cover “off the record, informal and under the radar” with no official records.

An average of ten schools in each local authority area, had sent children home for disciplinary reasons without recording it as an exclusion and the commissioner is calling for governors to challenge more, get schools to publish their behaviours policies online and get illegal exclusion reported to education watchdog Ofsted.

Now Pam Milner, of teaching union NASUWT, has warned head teachers if she became aware of the practice she would have to report it.

She said she had heard of troublesome pupils being removed from Bradford schools because Ofsted was inspecting and they did not want to be categorised as “needing improvement” or put in special measures.

Mrs Milner said: “Schools have to pay when they exclude a child and sending them on trips or getting them sent somewhere else means they do not have to pay.

“Illegal exclusion does go on and has gone on for years and years. I don’t know what provision is made for those children who cause problems if Ofsted is due in. They could be given work to do at home, or taken out somewhere on a minibus.”

Dr Atkinson said: “It is simply not acceptable for the education of thousands of young people to be disrupted, illegally, by the actions, or inactions, of adults whose job it is to show them an example to live up to, and to educate them.”

Councillor Ralph Berry, the executive member for young people and children’s services on Labour-run Bradford Council, said that he was “very concerned” about illegal exclusions if they were happening locally.

“We do not have many in Bradford and all high schools work together with robust arrangements in place to avoid this,” he added. “I would be very concerned if that was happening here and want to talk to Pam Milner about this.”