The NASUWT teaching union has been involved in action since last December, but has decided to escalate its campaign in the form of a strike today.
Chris Keates, General Secretary of NASUWT, said:
The escalation of the NASUWT industrial action is entirely the responsibility of the Secretary of State for Education, Michael Gove.
This action has been specifically designed to be pupil, parent and public friendly. We are endeavouring to ensure that is still the case with our escalated action.
The Secretary of State continues to fail genuinely to engage with the NASUWT and continues with his reckless disregard of the deep concerns of the teaching profession. This is a betrayal of not only the workforce but of every child and young person.
More top news
A BBC chief said reporters also had a responsibility to be sensitive in their broadcasts.
Ruth Smeeth is due to give evidence at a hearing involving party member Marc Wadsworth.
In the latest in the franchise, Marvel's superheroes assemble en-masse to face their biggest challenge yet.