The expert group commissioned by ministers to rethink the future of pupil assessment will not recommend major reform of national tests for 11- year-olds, The TES has learnt.
The news will disappoint unions and anti-Sats campaigners who had hoped the group's report, due next month, could trigger an abolition of the tests at key stage 2. Ministers have repeatedly referred to the group's imminent findings when questioned about the future of Sats.
News of the conclusions comes in the week the NUT voted unanimously to ballot for a boycott of all national tests in primary schools in 2010.
The union plans to act together with the biggest heads' union, the National Association of Head Teachers, which will vote on the same action next month. The NUT had hoped the experts' group could provide a way out of the dispute.
Speaking after the vote at the NUT's annual conference in Cardiff on Saturday, Christine Blower, the union's acting general secretary, said: "It could be that something very good comes out of the experts' group that fulfils all of our expectations, in which case great, we won't have to ballot for a boycott."
But The TES understands that the five-strong group will not recommend the changes to pupil assessment that the two unions want because its members are not prepared to go beyond the narrow limits set for it by government.
Union optimism has been fuelled by recent comments from ministers and two senior members of the panel of experts. Last week, Ed Balls, Schools Secretary, said KS2 tests were "not set in stone".
"I would be staggered if the expert group didn't have some ideas for changing them," he said, pledging to act on the panel's recommendations.
But the Government has given the experts' group very little scope for developing ideas for change.
The experts are not being asked to consider the pros and cons of KS2 tests. Their remit says only that they should recommend how schools can ensure that preparation for the tests is "proportionate, educationally appropriate" and does not inhibit the delivery of a broad and balanced curriculum.
One group member, Sir Jim Rose, had said the whole issue of testing was worth reviewing. At the time of his interim report on the primary curriculum in December, he described national tests as the "elephant in the room".
Fellow group member Sir Tim Brighouse recently described the uses of Sats for school accountability as crude and "19th century".
In February, Sir Tim suggested the group could go further than the Government had asked it to, saying he intended to "push the boundaries".
But The TES understands that the group is sticking to its remit, ruling out a fundamental re-evaluation of KS2 tests.
The group is also limited in what it can say about tests for 11-year-olds because it believes further pilot studies are needed before a conclusion can be reached on the Government's proposed alternative - single-level tests.
However, The TES understands that the group is considering radical proposals in other areas. If these relate to the school report card - another part of the experts' remit - they could yet offer some encouragement to unions.
Report cards have been suggested as alternatives to league tables. Unions believe it is the use of test results to compile league tables that makes the Sats so damaging.