Headteachers are preparing to block the Government's publication of the controversial league tables for 11-year-olds.
The National Association of Head Teachers will next week advise its members on how to wreck the proposed performance tables based on the results, school by school, of the national tests which start on Monday.
David Hart, general secretary of the NAHT, made clear the union's opposition to the Government's plans, announced in a major policy U-turn earlier this year. "We are in the process of advising our members about ways and means they can adopt to block the Government's wish to publish performance tables without interfering with the tests themselves."
Education Secretary Gillian Shephard had previously said that the tests are not sufficiently "bedded down" for performance tables to be published.
The dispute over league tables comes, perversely, as the Department for Education and Employment believes that it has now got the testing mechanism right.
This week it revealed that schools have voted overwhelmingly in favour of the Government's testing proposals, signalling the effective end of hostilities on the most controversial education issue since the last election.
Only the testing of Shakespeare and complaints about lack of funding remain as bones of contention, according to the first evidence from the Government's national survey of opinion, launched in January.
This leaves four fifths of schools backing the current arrangements and official proposals for the future. These include: retaining external marking; tests on mental arithmetic; a calculator-free paper for 14-year-olds; and maintaining the current balance of teacher assessment and tests.
Two thousand schools took part in the consultation, part of the Government's review of assessment and testing. It is the first comprehensive survey of national opinion since the test boycott in 1994.
"The first sampling indicates that the majority of schools - more than 80 per cent - support these proposals," said a spokeswoman from the Department for Education and Employment, results confirmed by the School Curriculum and Assessment Authority.
"From the responses we have seen to date, it would appear that testing is not the point of contention it once was," she told The TES.
The results will not please hard-liners in the National Union of Teachers who remain critical of external marking and have been pressing for much more assessment by teachers themselves.
The tests blew up in ministers' faces in 1993 when, led by the National Association of Schoolmasters Union of Women Teachers, the unions began a two-year boycott, complaining about workload.
The result was a humiliating political turnabout and the appointment of Sir Ron Dearing to conduct his major slim-down of the national curriculum. This was the beginning of the end for the then Education Secretary John Patten.
The following year brought the Dearing review and the introduction of external marking and subsidised supply cover to ease the burden on teachers.
Both the DFEE and the SCAA are claiming that all local authorities will take part in the national tests for 7, 11 and 14-year-olds which begin on Monday - despite the introduction of league tables of the 11-year-olds' test results.
Last year Nottinghamshire refused to cooperate after a row about the amount of money it should receive from the Government for supply cover.
Officials concede that the question of money is persistently raised by schools anxious to retain the subsidised supply cover currently offered by the DFEE.
Shakespeare tests for 13-year-olds remain problematic. The profession is also split about compulsory teacher assessment at key stage 3 in "foundation" subjects like music. This would raise the status of some departments, but mean additional work.
The survey results were welcomed by the NASUWT. "They don't surprise me, " said general secretary Nigel de Gruchy. "I'm pleased because it means we've made progress in adapting the system to the views of teachers."
John Bangs, education officer with the NUT, said: "The fact that ministers are seriously considering teacher assessment for Shakespeare, for example, demonstrates the advances that the NUT has achieved."