Malcolm Maciver, convener of the union's salaries committee, was unmoved by a local authority inspired media blitz suggesting that some teachers stand to gain more than 50 per cent in pay rises over the next three years (this would apply to unpromoted staff with five years' service, of whom there are only 681).
Speaking to The TES Scotland, Mr Maciver derided the employers for undermining an agreement between the two sides that there should be no "negotiating in public" and that "nothing is agreed until everything is agreed".
The authorities' summation of what they are billing as a pound;210 million pay offer over three years, linked to sweeping changes in staffing and work practices, including scrapping principal teacher posts, ended in acrimony after the unions accused the other side of selecting the most favourable elements from its package, an accusation the authorities had earlier levelled at the EIS.
Mr Maciver complained about accusations of a veto on progress in the Scottish Joint Negotiating Committee. "It's not a matter of a veto," he said. "It's a matter of moving forward on a basis of consent which is how we have always made progress in Scottish education."
He suggested the employers were embracing "a crude and simplistic teacher deficit model", which drew its inspiration from the very different situation in England and Wales. "The Government is clearly unable to contemplate any divergence between Scotland and England," he said. "Does that mean that Scotland has to come in the slipstream of what is happening in England and Wales? If so, it raises significant questions over the role of the Scottish parliament in relation to education."
Mr Maciver called on the Liberal Democrats and the SNP to say whether they support the strategy of the Labour-dominated management side which claims to be politically united. The two opposition parties have been seeking to exploit the gulf between the unions and Labour, accusing the Government of "teacher bashing" in the run-up to the Scottish parliamentary elections.
The EIS recognises that the employers' offer is "their opening shot which we have told them is unacceptable". Its executive council is set to approve counter-proposals on February 26. The union has already agreed to table an 8 per cent pay claim for the coming year.
But management sources were indicating this week that they expect the broad outline of the offer to be taken as a combined pay and conditions package, although there is room for negotiation.
The management also confirmed its wish for agreement to be reached by April, otherwise Scottish Office money to part fund the deal - unspecified but thought to be around pound;70 million - will no longer be available. The future of national bargaining in the SJNC will also be at risk.
Mr Maciver says such talk is no more than blackmail. "We are not prepared to rush into taking decisions when we have major reservations about how the management's proposals are going to stack up educationally," he says.
"There is no indication in the management's documents about how they see schools being managed in the future, a structure which is clearly understood at the moment. For us, that is a significant weakness.
"There is a huge question mark over how you are going to run secondary schools without principal teachers. How would you deliver the curriculum? How indeed would Higher Still have been delivered without principal teachers?
"So it's more important for us to make any changes work than making them happen according to some artificial timetable. It's more important to get things right."
The EIS also takes issue with the management's oft-repeated criticisms of the rigidities of national SJNC agreements which do not allow for differing circumstances in local authorities and local schools. The authorities say national bargaining has led to teachers falling behind on pay and conditions, a situation which has had to be rescued three times in the past 20 years by special review bodies.
Mr Maciver pointed out that agreement had been reached in the Millennium Review talks last year on the balance between national and local bargaining. The unions were prepared to honour that deal.
"So it is simply not true to say that we are hostile to problems of inflexibility," Mr Maciver said. "We have already reached a consensus that the SJNC should be amended to give the management the flexibility it wants."
Mr Maciver warned the local authorities and the Government that any final agreement would be put to union members in a ballot. "They will only get change if teachers vote for it. But their approach in trying to convince teachers is, to say the least, unfortunate."