The Teachers’ Union of Ireland has voted to accept the Haddington Road Agreement by a majority of 54% to 46%.
General Secretary John MacGabhann said that in accepting the deal, the TUI's 15,000 members had with strong reluctance taken a pragmatic decision to take the lesser of two evils.
He said the alternative was to be subjected to what he called the "unjust and discriminatory" Financial Emergency Measures in the Public Interest legislation.
That legislation, known as FEMPI, allows the Government to cut pay and conditions to a greater degree than the Haddington Road deal.
Mr MacGabhann said the TUI would continue to demand the removal of the FEMPI legislation.
He said the commitments in the agreement regarding improved salary scales for new teachers and lecturers, as well as the enhanced arrangements for the award of contracts of indefinite duration, must be implemented without delay.
TUI President Gerard Craughwell said the trust of teachers and lecturers in the Government had been severely undermined, and warned that there was a growing sense of anger and frustration.
He said the union's acceptance of Haddington Road did not represent an acceptance of the austerity agenda.
He added that there was no room for further education cuts in the forthcoming Budget.
The turnout for the TUI ballot was 65%.
A contingent ballot for industrial action (in the event that Haddington Road was rejected) was approved by a margin of 65% to 35%.
The TUI acceptance leaves the ASTI isolated as the only union which has rejected Haddington Road.
The only union which has to still to deliver the result of its ballot is the Irish Federation of University Teachers, which represents around 3,000 lecturers.
It will announce the result on Monday.
Earlier today it was announced that ASTI members had rejected the Haddington Road Agreement by 63% to 37%.
They also balloted for industrial action in the event that the deal was rejected. That ballot was 65% in favour with 35% against.
The ASTI had recommended a rejection of the deal, while the TUI issued a neutral recommendation to members.
The ASTI represents 17,000 secondary school teachers, while the TUI represents 15,000 teachers at second- and third-level.
Mulvey says rejection unfortunate
The chief negotiator of the Haddington Road Agreement has said that as far as he is aware, there is no prospect of talks being reopened with the ASTI.
Labour Relations Commission Kieran Mulvey described the decision to reject the pay deal as unfortunate, noting that the ASTI was the first public service union to reject it.
He said the Haddington Road talks had concluded and he did not see any prospect of them reopening for the moment.
He said that was a matter for the parties themselves, but from the point of view of his Labour Relations Commission negotiating team, the talks had concluded.
The deal, which came into effect on 1 July, provides for longer working hours, pay cuts for those earning over €65,000 and increment freezes of variable duration depending on the level of pay.
Crucially for teachers, it also sees the abolition of a €1,700 a year allowance for supervision and substitution duties, with the prospect of partial reimbursement after the deal expires.
However, it also provides protection from compulsory redundancy, and offers the prospect of pay restoration for those earning less than €100,000 after the agreement expires in 2015.
Unions that reject Haddington Road will lose those protections and will have a total increment freeze for three years.