The government has created an “Emperor’s New Clothes curriculum”, which is “so vague and nebulous as to be meaningless and impossible to implement”, a headteachers’ leader will warn today.

Brian Lightman, general secretary of the Association of School and College Leaders, will tell the union’s annual conference in Birmingham this morning that the proposed national curriculum is an “illusion”, which is too vague and “old-fashioned” to be relevant to students.

In his speech, Mr Lightman (pictured) will say that his members feel “deeply frustrated and frequently incredulous at the way the profession has been sidelined” in drawing up the curriculum. As a result, many heads are concerned that it is “not fit for purpose”.

“I am reminded of the story of the Emperor’s New Clothes, in which a king unquestioningly believes that his new clothes are the finest in the world, when in reality, they are an illusion and he is actually naked,” Mr Lightman will say. “This National Curriculum is actually an Emperor’s New Clothes curriculum.”

The curriculum will be introduced in September for all subjects and all ages except Key Stage 4 English, maths and science, which will follow a year later.

Education secretary Michael Gove has said that the new version will be more rigorous and help students progress to university or the workplace. 

But Mr Lightman will express his concern that it will not be statutory in academies and has been created by “working backwards” to match the new, reformed GCSEs.

Mr Lightman will also take on Mr Gove’s arguments over rigour. “Despite all of the rhetoric about rigour, large parts of this secondary curriculum are so vague and nebulous as to be meaningless and impossible to implement… So what has happened to the rhetoric about defining the core knowledge that people should have? Where is the guarantee of rigour?”

School leaders, Mr Lightman will say, will be left to “rescue the curriculum before it withers away, bringing it back to life with a vision and values which inspire and motivate our young people”.