Public sector strikes: NUT's Blower defends 'legitimate ballot'
10 July 2014 Last updated at 00:06 BST
The head of the NUT has defended her union's mandate for strike action, following criticisms of the date and turnout of the ballot.
In an interview for Newsnight, Christine Blower said the ballot, which was conducted in 2012, was for "discontinuous action with no end date"
Members of the union will join firefighters, civil servants and local government staff in the protest on Thursday, part of a dispute over pay and other issues.