Islamic fundamentalists plotted to oust headteachers at Birmingham schools and replace them with supporters who would impose strict Islamic principles, it has been alleged.
Senior education managers at Birmingham City Council were investigating documents purporting to claim that jihadists had spread false allegations about school staff members to prompt their removal by school authorities and create space for fundamentalist teachers to move in.
The plot was dubbed "Trojan Horse".
The documents claimed to show leaked correspondence between two fundamentalists involved in the plot, one in Birmingham and one in Bradford.
Their letter claimed that once a headteacher has been removed, they would try to install a replacement from its own group to enforce education of pupils along hardline Islamic principles.
That would include segregating boys and girls in a bid to make the schools religious academies.
The documents, seen by the Birmingham Mail, claim that four schools - Adderley Primary, Saltley School, Park View School and Regents Park Community Primary School – had changed leadership because of the operation.
The documents also outline a plan to implement similar schemes at schools in Bradford and Manchester.
The letter said: "We have caused a great amount of organised disruption in Birmingham and as a result we now have our own academies and are on our way to getting rid of more headteachers and taking over their schools.
"Whilst sometimes the practices we use may not seem the correct way to do things you must remember this is a 'jihad' and as such all means possible to win the war is acceptable.
"We have an obligation to our children to fulfil our roles and ensure these schools are run on Islamic principles."
The group is said to have targeted schools which struggle to meet Ofsted standards and which have a high Muslim population.
Supt Sue Southern, head of West Midlands Counter Terrorism Unit, said: "Birmingham City Council brought the content of a letter they were investigating to the attention of West Midlands Counter Terrorism Unit requesting we make an assessment of whether any criminal offences had been committed.
"The assessment at that time and today is that the allegations in the letter were for further investigation by Birmingham City Council and Department for Education and were not a matter for the police."