The president of the NASUWT teaching union is set to attack the government's education reforms, claiming they are distracting from the task of teaching children.
Mick Lyons will tell NASUWT's annual conference in Bournemouth hat education is being used as a "political football".
In a speech, he will say: "Daily denigration of the work and commitment of teachers, false claims of plummeting educational standards, and attacks on jobs, salaries, conditions of service and pensions are leaving colleagues heartily sickened and demoralised."
More top news
Spring takes a hike - for the time being
A number of Britons are feared stranded on Mount Everest after the Nepal earthquake triggered a deadly avalanche on Saturday.
Prime Minister defends royals' decision to give birth in a private hospital - instead of going with the NHS