EDUCATION will move to the heart of the political agenda in Scotland this week with a speech by the first minister to headteachers, a debate in parliament, and the revelation that the top teaching union will effectively back an SNP policy during the election campaign.

Jack McConnell, the first minister, will outline plans to ease the move from primary to secondary school during a speech in Glasgow tomorrow to headteachers.

Mr McConnell is to set out how he hopes to tackle the problems schoolchildren face during the major transition to secondary education.

One of Mr McConnell's aides said: ''A lot of research has been done and it illustrates that children making the transition can have some problems.

''The first minister will be setting out the first steps towards addressing what is a problem that has been around for as long as we can remember.''

The first minister would also be announcing other education reforms designed to drive up standards, including new powers for headteachers to set their own priorities.

He will demand teachers offer more vocational classes within the school system, and encourage greater links with colleges and businesses.

It is understood that Mr McConnell will call for greater use of specialist teachers to encourage pupils with an interest in subjects such as music and sport. MSPs are due to discuss the subject of innovation in schools during an executive-led debate on Wednesday.

A central plank of the SNP manifesto next spring will be the reduction of classes in the first three years of primary to a maximum of 18, to allow teachers to give children a flying start to their formal education.

Yesterday, it emerged that the Educational Institute of Scotland is to launch its own campaign for a cut in class sizes, effectively putting a major union in the same camp as the SNP in the run-up to the

election.

Cathy Jamieson, education minister, defended the executive's record on education and dismissed calls from the SNP for a dramatic cut in class sizes.

She said that, despite concerns over class sizes, the teaching unions had welcomed initiatives to drive up the number of classroom assistants, adding: ''We have to ensure we get more specialist teachers in.''

However, Michael Russell, the SNP's education spokesman, said the ''biggest single contribution you can make'' to boosting educational achievement was to cut class sizes to 20 or fewer.

He said: ''What Jack McConnell is doing and what Cathy is doing is rejecting all the ideas that are coming from south of the border, but they have no ideas of their own. But here is a really big idea that will make a huge difference.''

He said that, under SNP proposals, young people would be helped into vocational education earlier and the exam system should be simplified.