Tory industrial relations law is likely to rescue Educational Institute of Scotland leaders ambushed by the hard left over further cuts in class sizes.

Negotiators have been given until December to thrash out an agreement on class size cuts with local authorities and the Scottish Executive after delegates last weekend voted 152-141 to stiffen the union campaign with the threat of industrial action.

In the absence of firm moves towards a maximum of 20 in each class within what is in reality a four-month period, leaders have been instructed to organise a members’ ballot to support their campaign, the only significant victory for the left-wing.

But the warning about the significance of class-size cuts is likely to be emasculated by employment legislation which stipulates that any action must be within 28 days of a ballot. Even the movers of the tougher line on talks in the Scottish Negotiating Committee for Teachers accepted there would be no immediate ballot in the new year if their pressure fails.

Speaking after the critical motion at the annual conference in Dundee, Ronnie Smith, general secretary, said there was a strong feeling of unity among teachers in pressing for smaller classes. The issue was one of tactics.

“If there is no successful conclusion, the instruction is we carry out a ballot but when that ballot is conducted will have to be looked at by the council at the time in the light of all the circumstances. Industrial action ballots have a 28-day shelf-life so it’s not something you just do and tuck the result in your back pocket,” he explained.

A ballot could be any time in 2005 or 2006. “It’s certainly not to be interpreted that there will be a ballot in January,” Mr Smith said.

It is three years since EIS school members voted over the workload of internal assessment in the Higher Still programme. That led to pressure on the ministers and in turn a subject-by-subject review after a members’

survey rejected a boycott. There was no disruption and last weekend for the second year running, no reference to the reformed curriculum and assessment system in upper secondary.

Union leaders may run a similar strategy on class sizes to deflate what they regard as unrealistic left-wing demands. In his conference address, Mr Smith nevertheless appealed to ministers “to be bold” and go beyond the class size commitments they have already given. There were now sufficient teachers and physical accommodation because of the drop in pupil numbers to make this possible.

In the conference debate, Hugh Donnelly, Glasgow, said more individual focus in the classroom, more integration of pupils with social and emotional difficulties and more assessment changed the face of classrooms.

“It is time for the EIS to become much more assertive and confident in pursuing lower class sizes,” he said.

“This is not a simple matter of number-crunching. It’s about more effective teaching and learning, improved classroom management and creating a more positive classroom climate, more interaction with the teacher and improved relationships between teacher and pupil,” he said.

Eric Baillie, Dundee, speaking for the union leadership, rejected the tight timescale for talks, arguing that further cuts in class sizes would depend on the balance between teacher supply and accommodation. It was “plainly daft” to allow negotiators only four months to achieve longstanding union targets.

Nationally, ministers are committed by 2007 to cut classes to a maximum of 25 in P1 and 20 in S1 and S2 in English and maths.