One in three teachers in England, Wales and Northern Ireland plan to quit the classroom within five years. This is according to the National Education Union. But, why are some teachers swapping the classroom for a different career?Jonathan Samuels talks to the joint general secretary of the National Education Union, Kevin Courtney, about morale in the industry. Leila MacTavish, head of Ark Teacher Training, explains how educators can use body language to keep control of their lessons, and headteacher Ruth Luzmore reveals why she's leaving the job she loves after 17 years