Donald Dewar, the Secretary of State, wants to shake up teachers’ promotion posts to keep “good teachers” in the classroom, fuelling speculation that a Scottish education Bill could be on the cards.

In a speech to party members in Glasgow last week, billed as the start of Labour’s fightback against a strong SNP showing in opinion polls, Mr Dewar effectively launched his party’s platform for next May’s elections to the Scottish Parliament.

He put education at the top of the agenda. But most of his five-point programme was a repackaging of existing policies - early intervention, headteacher training and community schools. He did add two unexpected items: summer schools to boost children’s learning and restructuring pay and promotion.

The latter changes, however, require the consent of unions and education authorities in the Scottish Joint Negotiating Committee. The Educational Institute of Scotland would be wary of any two tier pay scale which pitted “excellent” teachers against the rest.

But Ken Wimbor, the EIS assistant secretary, said the union did not disagree that there should be some mechanism to reward classroom teachers so they were not forced to opt for the management track. But he pointed out that senior teachers were created back in the 1980s to do just that. There is general agreement that the senior teacher post has not worked out as intended and has effectively become an arm of management.

The EIS would be unlikely to accept the “advanced skills teacher” now being introduced in England. If Mr Dewar does not win union consent, the only way he could get his way would be to remove the statutory basis for the SJNC which currently gives its agreements the force of law.

This change has long been desired by the Labour-run education authorities. They believe it is unnecessarily rigid and inflexible to make everything from composite class sizes to promoted post structures the subject of collective bargaining at national level.

The Scottish Office has previously set its face against legislating on Scottish education, because it will become the responsibility of the Scottish parliament within two years. But pressure is building from the local authorities. In addition to amendments to the SJNC, they want changes to the placing request legislation and the removal of opting out from the statute book.

The Government would also find it easier to implement its key election pledge on class sizes if there were new placing request provisions, allowing authorities to turn pupils away from primary one to three classes once they reached the maximum of 30.

Some authorities also want freedom to create larger multi-stage classes to avoid the costly formation of extra classes to achieve the reduction. But class sizes, including the numbers in composited groups, also have to be agreed through the legal framework of the SJNC.

Scottish Office ministers must now decide whether education legislation requires tidying up as a matter of priority, or whether it should be left to the Scottish parliament. The decision could hinge on the outcome of the millennium review, a joint enquiry by unions and management into the way forward for education, due to finish its work by the summer.

Any changes agreed in the review which touch on national agreements will have to be referred to the SJNC. But the authorities are not hopeful of securing the changes they want.

Elizabeth Maginnis, the management side convener, said: “It is not clear there will be consensus on issues such as those raised by Donald Dewar. We will then have to give serious consideration to the implications should a consensus not emerge.”

In his speech Mr Dewar adopted a more challenging line on Scottish education than hitherto, saying it “can no longer afford to rely on reputation”. And while in the past he has been coy about what the Government would do if schools continued to underperform, last week he said: “If standards do not progress, we will not hesitate to intervene to make it happen.”