He said: "I am only one of three or four heads I know in the past 10 years who has not taken ill-health retirement. Everybody else has."
Mr Marsh reached retirement age this year after 19 years as head of St Mary Magdalene Church of England primary in the London borough of Islington.
"I managed to make it, although I'm delighted I am not having to go on until 65," he said.
Mr Marsh said the biggest change for teachers in recent years has been the mushrooming of paperwork. "Teachers are dragged away from creative interfaces with children to boring interfaces with forms."
He is confident, though, that the current trend in schools of resisting over-prescription will continue.