The Education Secretary has intervened directly in four North East academies - warning he will impose his own governors on the schools unless they improve.
Ministers wrote to the schools on behalf of Education Secretary Michael Gove demanding they explain how they planned to raise standards.
The “pre-warning letters” were the first stage of a process which could lead to Mr Gove appointing his own directors to an academy trust or local governing body if improvements are not made.
Ministers argue that academies will improve standards by freeing schools from the grip of local councils.
A letter sent on November 19 to the Academy 360 Trust, which runs Academy 360 in Sunderland, criticised results in Key Stage 4, which refers to pupils age 14 to 16.
It read: “the Secretary of State considers that the standards of performance at Key Stage 4 at Academy 360 are unacceptably low and are likely to remain so,”
The letter warned: “The Secretary of State is able to issue a Warning Notice to the Governing Body of the Academy Trust . . . and if that Warning Notice is not complied with to the Secretary of State’s satisfaction, then he will be entitled to appoint Additional Directors to the Academy Trust.”
Sir Ken Gibson, who became Executive Head Teacher of Academy 360 in September least year, said: “We are addressing the concerns raised by the DfE. There have been massive improvements over the last 12 months. The primary results were fabulous and the secondary improvements are a work in progress.”
Earlier this year the school achieved record high results for Key Stage 2 Sats.
A letter was also sent to Academies Enterprise Trust (AET), which runs Eston Park and Gillbrook Academies in Middlesbrough. The letter, dated October 15, said Mr Gove was concerned about plans to merge the schools and about poor GCSE results.
It said: “The Secretary of State considers that the standards of performance at both Gillbrook Academy and Eston Park Academy are unacceptably low, and are likely to remain so following the merger of the academies, unless the Secretary of State intervenes.”
A spokesman for the Trust said: “AET recognised the need for significant intervention at both schools earlier in the year and immediately appointed one of our most experienced staff to the position of Interim Principal at Eston Park. The summer GCSE results revealed a massive improvement of over 20% in good passes with English and Maths.”
And a letter was sent to the Governors of Red House Academy in Sunderland in January 2012. It has only now been published by the Department for Education.
The letter highlighted poor GCSE results in 2011 and again warned that Mr Gove had the power to appoint his own governors. Since then, the number of pupils achieving five or more GCSEs at grades A* to C including English and Maths has risen significantly, from 19% in 2011 to 36% in 2012.
Mr Gove recently criticised councils in the North East for failing to encourage new academies.
Earlier this month, he said: “A lot needs to be done in the North East in order to improve education.
“One thing we need to do is ensure that local authorities end their opposition to academisation and free schools.”