Roger Woods, 50, aimed to make Cwmcarn Comprehensive, near Risca in South Wales, the first grammar school in the principality. But he will stand down at the end of the summer term, complaining that government opposition to selection will damage pupils' education. "There's no doubt that the children are the last thing on their mind. The political agenda leads them - I think it verges on the criminal," Mr Woods said.
The school is in the Islwyn parliamentary constituency. When it went grant-maintained in 1991, the seat was held by Neil Kinnock, which led to allegations that the move was an attempt to embarrass the then Labour leader.