A fresh round of teachers' strikes could cause major exam disruption after their union recommended rejecting an "insulting" pay offer from the Government following intensive talks.
National Education Union co-leader Mary Bousted has said teachers do not want to take industrial action on exam days but refused to rule it out if members agree to turn down the pay offer.
Following weeks of talks, the Government offered teachers what the NEU says amounts to a £1,000 one-off cash payment for the present school year and a 4.3 per cent consolidated pay rise for most teachers the following year.
The NEU, which is the largest teaching union, has recommended that members vote to reject this.
Ms Bousted told BBC Radio 4's Today programme: "Our executive committee looked carefully at the offer and decided it was really insulting and that the union had to offer advice to members, who will either take that advice or ignore us."
Asked whether strikes could disrupt exams, she said: "We really hope that that doesn't take place.
"What we hope is that, if the members do reject the offer, we want to go back to the Government and say 'You have to do better', reopen negotiations, and let's see if we can get an offer that members will find respectable."
Asked again about whether strikes will disrupt exams, Ms Bousted said: "We will plan more strike dates. We don't want to disrupt exams and we will try to ensure that we do reopen negotiations."
Pressed on the issue a third time, she said: "We have conference next week, and conference will decide the plan of action, but no teacher wants to disrupt exam dates at all, so it's up to the Government."
The NEU is also holding an election for its next general secretary, with members to vote for either Daniel Kebede or Niamh Sweeney.
Ms Bousted also clashed with Today presenter Nick Robinson when he asked her whether she considers Mr Kebede to be an "extremist", who would plan strikes on exam days.
"I think that's an outrageous slur," she said. "We're not getting into personalities four days before an election.
"I wouldn't describe either of my successors as an extremist.
"General secretaries don't decide policy for the union - they have an executive, and they have a membership.
"I think this is quite outrageous, actually. You're bringing what is a really serious issue about the future of teachers, about the current state of teachers in the classroom, down to personalities.
"I think that is really base, it demeans the programme. I'm very sorry you've done that."
The Government has described its offer to teachers as "fair and reasonable".
A Department for Education (DfE) spokesman said: "The Government and the education unions - NAHT, ASCL, NEU and NASUWT - have engaged in intensive discussions over the last 10 days.
"The Government has put forward a fair and reasonable offer, backed with funding for schools.
"The offer provides an average 4.5 per cent pay rise for next year, puts £1,000 into the pockets of teachers as a one-off payment for this year, and commits to reducing workload by five hours each week.
"This is a good deal for teachers that acknowledges their hard work and dedication."
