Teachers' warnings over academies
The two biggest teachers' unions are stepping up their attacks on the government's rapid expansion of academies in England.
More than half the secondary schools in England have become, or are in the process of becoming, academies, with some being forced into the change in the hope of improved performance.
The NASUWT says it believes academies, which can set their own salaries, are being used to help dismantle national pay agreements.
Reeta Chakrabarti reports.