The nationwide launch of new Higher qualifications, due to be taken by students across Scotland from next year, has been thrown into doubt after Edinburgh and Glasgow councils refused to back their full-scale introduction.
The City of Edinburgh Council told TESS that after talks with its headteachers, it would give its schools until the 2015-16 academic year to bring in the qualifications in all subjects, a year later than the government had planned. Work introducing the new National qualifications had contributed to the delay, the council said.
Glasgow City Council added that it was still in discussion with its heads, but said the introduction of the Highers would depend on how similar they were to the existing qualifications and whether they met the individual needs of young people.
West Lothian Council also said that it was unsure whether its schools would be introducing the new Highers in all subjects next year.
The government's intention had been that S4 students studying the new National qualifications this year would be able to embark upon the new Higher in 2014. The qualification has been specifically designed to follow on from National 5 and to chime with Curriculum for Excellence.
Despite the reservations of some of the country's biggest local authorities, guidance due to be issued this week by the Curriculum for Excellence Implementation Group was expected to urge schools to press ahead with the changes.
But teachers are concerned that a rushed introduction of the qualifications could put students at a disadvantage and increase workloads for school staff.
Larry Flanagan, general secretary of the EIS teaching union, said the decision as to which qualification was best - the old or the new Higher - should be taken at school level.
"We will be raising our concerns with both the Scottish government and the SQA (Scottish Qualifications Authority), and seeking agreement that the decision on what Higher to use will be school-based and taken in association with parents and pupils," he said.
Ken Cunningham, general secretary of School Leaders Scotland, said that significant changes in some subjects, including biology, would cause extra work for staff.
But he did not support delaying their introduction. The new Highers had been designed to fit in with the Nationals, meaning that it made "logical sense" to push ahead with their roll-out, he said.
He added that the old Higher would be phased out completely by 2015-16, so any students who took the qualification next year and failed would be unable to re-sit.
"It really is better that we hold the line on this and keep moving forward," Mr Cunningham said. "But where there is significant change in the new Higher, SQA and Education Scotland should supply as many resources as possible to assist in the deployment of it. That will vary from subject to subject."
According to the Scottish government, schools have made "tremendous progress" in the delivery of the new qualifications. "It is vital to the interests of learners that this momentum is maintained," a spokesman said.
Of a handful of councils contacted by TESS, two said they would be introducing the new Higher wholesale, with few, if any, exceptions. In North Lanarkshire, the old Higher would be run only in "exceptional circumstances", a spokesman said. And a spokeswoman for Perth and Kinross said there would be "no differentiation between the old and new Highers".
Fife said it was awaiting the outcome of a national meeting being held today before settling on a position.
Scottish Borders Council was also awaiting the outcome of the same curriculum, assessment and qualifications meeting being held by the Association of Directors of Education in Scotland.
In 2011, the CfE implementation group issued guidance in relation to the Nationals, saying that only "on an exceptional basis" could individual departments - but not whole schools - present students for the old exams.
East Renfrewshire Council, however, broke ranks and postponed the introduction by a year.