Are our children being failed by incompetent teachers? In the last 20 years only two teachers have been struck off for incompetence in the whole of Scotland. That is despite the fact that some education experts put the figure of bad and failing teachers closer to 2,500. With new research showing that the standard of the teacher is the most important factor in a child's school education, more important than class sizes or the curriculum, we ask why so many bad teachers are being allowed to teach. Talking to parents, head teachers and school watchdogs, reporter Sam Poling reveals the shocking effects that bad teachers are having on our children and asks why more is not being done to rectify it.