Parents, voters, ministers - do the maths: if we run out of teachers, who will teach our children?

Lucy Kellaway loves teaching. She came to it remarkably late, deciding to retrain at 58 after a long career in financial journalism, but is so evangelical about the switch that she set up a charity to help others do the same. Now Teach has since supported more than 800 people into the classroom, many leaving lucrative careers in banking or law and disproportionately entering areas of desperate shortage, such as science and maths.