Teachers at a London school went on strike today after their pay was docked for taking part in industrial action.
About half of the teachers at Stratford Academy in east London have taken part in the walkout, organised by two teaching unions.
It is understood that the school has remained open.
The National Union of Teachers (NUT) and the NASUWT teaching union have been taking joint national industrial action, short of strikes, in recent weeks over issues including pay, pensions and workload.
Teachers taking part in this action at Stratford Academy have been hit with "punitive fines", the unions claim.
Salaries have been cut by 15%, they said.
The school said that governors had taken the decision to reduce the pay because the action meant that the teachers were not taking part in tasks around lesson planning and observation, which they believed was detrimental to pupils and in breach of contract.
NUT general secretary Christine Blower said the teachers were "dedicated and committed to pupils".
"Instead of penalising and punishing them, the governors should focus on pressing the Secretary of State to resolve the national trade dispute and end his relentless attacks on the teaching profession," she said.
NASUWT general secretary Chris Keates said: "The teachers deeply regret the disruption pupils and parents now face but it is entirely due to the hostile and vindictive actions of the governors and school management."
