Mary Bousted, general secretary of the ATL, said that while she disagreed with the testing regime introduced by the Conservative government, the real “problem” was the curriculum.

“We have children who are learning the names of words in the hope that this will make them better readers and writers. It won’t. Instead they should be being asked to read widely and write creatively in their classrooms.

“I would say that the primary assessment system is the carbuncle on the boil that is the primary curriculum,” Dr Bousted added.  

Her comments come after a fraught term for primary assessment in which one major test was cancelled following a leaked paper and there were complaints that another was so difficult it reduced pupils to tears.

Parents even attempted to stage a “strike” ahead of the Key Stage 1 tests by pulling their children out of school for a day in protest against the tougher tests.

Speaking at the Northern Rocks teachers’ conference in Leeds, the union leader said the support for such a curriculum came from a group she described as the “new blob”, which was formed primarily of former Teach First teachers.

“These are people who may well have enjoyed a classical education and the benefits that come with it, but they have no understanding of real life,” Dr Bousted added.  

It is not the first time Dr Bousted has commented on the so-called “new blob”, whom she described as wanting to deal only “with a rose-tinted view of teaching which bears only a passing resemblance to the reality of working in too many schools”.

Her words were met with outrage on Twitter, with a number of people hitting back at the description.