The introduction of new Higher exams could be hit by widespread delays of up to a year in a range of key subjects, MSPs were warned this week.
New Highers in maths, physics, chemistry, biology and computing science were expected to be put on hold in many schools across Scotland, despite a start date originally being set for this June, a union leader has said.
Larry Flanagan, general secretary of the EIS teaching union, told the Scottish Parliament's Education Committee that the subjects were suffering delays because they had experienced the most significant change to course structure under the new Curriculum for Excellence.
He said that although about 80 per cent of subject areas would proceed with the new exams in the summer, schools would struggle to run them in sciences and maths.
"It is not surprising that these are the content-heavy subjects, which have potentially experienced bigger changes in terms of course structures," he told the committee, which was seeking reassurance that the new courses were on track.
Ken Cunningham, general secretary of headteachers' organisation School Leaders Scotland, agreed that there was likely to be "more complication and difficulty" when it came to introducing the new Highers in these subjects. But he said it was hard to second-guess how common problems would be.
"Delay in these subjects is not inevitable," he said. "A lot will come down to individual circumstances and confidence."
Despite his warnings, Mr Flanagan said that about a third of Scottish councils would have no choice but to push on.
Nine local authorities had issued blanket instructions to schools that they should go ahead with the new qualification in all subjects, ready or not, he said.
He added that this flew in the face of government guidance, which recommended that decisions on the new Highers be school-based, and warned that where local authorities had imposed the introduction of the new qualification on schools, the union would be prepared to enter into dispute.
Richard Goring, professional officer for the Scottish Secondary Teachers' Association, said he shared the concern that councils were pushing schools into new Higher subjects before they were ready.
In some local authorities no professional dialogue was taking place at all, he said.
But Graeme Logan, Education Scotland's strategic director for school years, said he was unaware of any councils taking blanket decisions on the new Higher. Most schools would not decide until the end of April which subjects they would be introducing, he said.
However, schools sticking with the existing Highers across the board would be challenged, he warned.
Minister for learning Alasdair Allan told the committee that the "natural option" for students was the new Higher, given that it had been specifically designed to chime with CfE. However, in the "unusual circumstances" where it was in the best interests of students to take the current Higher, the flexibility was there to allow that to happen, he said.
Exam body the Scottish Qualifications Authority (SQA) said that official figures on the uptake of the new Highers would not be available until the start of the next academic session in August.
Last Friday, the Scottish government announced a package of support for teachers worth pound;5 million to support the introduction of the new qualifications. It included pound;4.75 million for councils to fund time for teachers to prepare, along with an additional in-service day next year.
Meanwhile, the SQA announced it would be modifying its approach to the quality assurance of the new National qualifications with immediate effect, in response to teacher feedback. The implementation of the new qualifications in Scotland has come under fire from teachers who say they have been hit by "a workload tsunami". According to EIS, "anger and disappointment and frustration" with the SQA is widespread.
Teaching unions welcomed the cash injection and news that the quality assurance process would be simplified. However, the money had come too late for the new National qualifications, with just six teaching weeks left before students sat their exams, Mr Flanagan told the education committee.
"The support is welcome but it has come after the fact. We would almost have preferred it to be in there as part of the planning process," he said.