The government looks set to outline its plans next week for the introduction of school report cards which will classify every primary and secondary school with a single grade.
The proposals will be published in the white paper, 21st Century Schools. They are expected to be met with strong opposition from teachers' unions, which oppose the idea of a giving a school a single A to F grade.
Last month, the Government's expert group on assessment recommended that report cards should be introduced for a wide range of areas, such as child wellbeing, pupil satisfaction and exam results.
It remains unclear how the report cards will be administered. Ofsted admitted in a Commons schools select committee last month that it had "no idea" who would be grading the schools.
But teachers' unions have made it clear they do not believe a report card that gives a school a single grade is the right direction for the Government to take.
Mick Brookes, general secretary of the National Association of Head Teachers, said: "We will be interested to see what will be in the white paper, and we support the direction the Government seems to want to travel in.
"But we are against a large letter being on the report card denoting a school's category. We think this would be incredibly misleading for everyone, especially parents."
The timing has been criticised because a general election is expected in the next 12 months, and because there is speculation that Ed Balls, the Schools Secretary, is about to leave the Department for Children, Schools and Families and take over as Chancellor in the government reshuffle many pundits are predicting will happen next week.
John Dunford, the general secretary of the Association of School and College Leaders, said the year before an election was no time for a new white paper to be issued.
"We don't need a white paper full of whacky new ideas that will then have to be implemented in a rushed education bill, in what will be a truncated parliamentary session in the autumn," he said. "What is required is to take the best of what is happening currently and to put this in the shop window of what is an increasingly improving schools system."
David Laws, the Liberal Democrats' education spokesman, said he hoped to see report cards replacing league tables as a true indicator of schools' performance, but was resigned to seeing more "gimmicks".
"I fear that this white paper will duck the opportunity to make the reforms our education system so desperately needs," Mr Laws said.
"It is likely to be full of gimmicks and top-down initiatives, but says nothing about how this Government could loosen its stifling grip on our schools so that teachers can work creatively to raise standards.
"Unfortunately," he added, "it will also fail to radically reform school funding to make it fairer, or cut infant class sizes to a more acceptable level."
A Conservative spokesman said: "All we've heard so far about the new white paper has been deeply underwhelming.
"The Government should be introducing legislation to give teachers more power to keep order in the classroom, and to sort out the exam system. Instead, all we've seen is a timid proposal from the Prime Minister to give parents an extra mechanism to complain about schools."