Kenny Frederick, a headteacher and member of the NAHT executive, has accused the Education Secretary Michael Gove of wanting to "bring us back to 1950s".
Speaking on the BBC's Radio 5 Live, she said that Mr Gove has not listened to teachers and that his plan was destined to "fall flat on its face".
Mr Gove is expected to receive an angry reception when he speaks at the NAHT conference in Birmingham this afternoon.
More top news
Showers continue across some southern and western areas tonight.
Two people are being treated in hospital after an "explosion" in a flat in West Dunbartonshire.
Tom Billings, 22, went missing in Canada in December 2013 during an eight-week trip of North America.