Schools will suffer because the quango charged with developing the curriculum and qualifications will struggle to recruit staff with sufficient expertise and experience, heads' leader have warned.
The new Qualifications and Curriculum Development Agency is already facing the loss of nearly half its staff because of a relocation from London to Coventry.
But John Dunford, Association of School and College Lecturers general secretary, fears the exodus of expertise is being exacerbated by the uncertainty hanging over the agency.
In July, Tory leader David Cameron said that "the QCDA must go". He says a Conservative government would improve accountability by moving responsibilities for the national curriculum to the Department for Children, Schools and Families.
Dr Dunford said: "Any organisation losing so many of its staff is already clearly at risk," he said. "But my concern is that good people will be put off applying for QCDA senior posts because of the Conservatives' intention to abolish it."
But the agency says 55 per cent of its staff have opted to move with it to the Midlands. It has also recruited 215 personnel from the West Midlands and says it has "high quality knowledge capture procedures in place".
"Experienced staff will be relocating and we have already recruited quality senior staff to help shape and develop our new organisation and to lead on major policy areas," a spokesperson said.
But the fledging agency has suffered the loss of two big hitters from its predecessor organisation, the Qualifications and Curriculum Authority (QCA), with the departure of Ken Boston, chief executive, and Mick Waters, head of curriculum.
Unions originally claimed the move from the QCA's upmarket Piccadilly HQ would lead to the resignation of 85 per cent of employees.
Staff have expressed concerns about the calibre of the new location: "There is no Fortnum's in Coventry, a city twinned with Volgograd and Dresden," the husband of one employee wrote.
Dr Dunford also fears the consequences of the Conservatives' plan to bring the QCDA's responsibilities back in house.
"The whole system will suffer if the Government doesn't have good, independent advice," he said. "If the QCDA doesn't exist, we have yet to learn how a Conservative government would get that advice."
Ofqual, the exams regulator that formed the other half of the old QCA, has already completed a move to Coventry, where it employs about 160 people, 36 of whom relocated from London.