An extra £1bn was spent by the Government in the last two years on turning schools into academies, the spending watchdog has said.
The National Audit Office (NAO) said the Department for Education (DfE) was “unprepared” for the financial impact of rapidly expanding the programme.
In a new report, the NAO said the department had initially failed to anticipate the scale of interest from schools who would want to take on academy status.
Academies are semi-independent state schools with freedom over areas such as the curriculum and staff pay and conditions.
Soon after the 2010 general election, Education Secretary Michael Gove announced he was opening up the programme to allow all schools in England to apply for academy status.
But a new NAO report concluded that while this expansion was a “significant achievement”, the DfE was not ready for it. It found that between April 2010 and March 2012, the DfE had to find an estimated £1 billion of additional costs.