Chris Woodhead told a Conservative party conference in 2001 that he could recall the last class he taught as head of English at Gordano school, in Portishead, Somerset, in 1976.
"Janet Hockings and Derek Pike were three to five minutes late," he said.
"They came swaggering in, knocking into other pupils."
However, only Janet Hockings had even a hazy recollection of Mr Woodhead and she thought that he taught maths.
Mr Pike said: "I remember a few teachers. But Mr Woodhead isn't one of them."