Colin Moran, head of Henry Moore juniors in Castleford, West Yorkshire, said: "I witnessed my weakest pupils sit there with body language that told me they were lost, because most of the questions were too difficult and they didn't understand.
"I saw all the failure and rejection in those kids' faces. I have worked for 34 years to change that by getting all our pupils to believe in themselves and their abilities."
He said the emphasis placed on the three Rs meant there was not enough time to teach the rest of the national curriculum.
NAHT conference, 4,5