Dumfries and Galloway has become the first council to break the mould of mixed-ability classes in the first two years of secondary school but has run into immediate opposition from one of Scotland's leading educationists.
Professor Brian Boyd, director of the Quality in Education Centre at Strathclyde University, maintains there is no research evidence to justify a change that will be welcomed by the Scottish Office, which has long campaigned for alternatives.
Ministers' arguments about a failure to achieve in the first and second years of secondary are underlined this week in the Inspectorate's report on Standards and Quality in Scottish Schools (page three). Douglas Osler, senior chief inspector of schools, describes provision as "disappointing". Mr Osler's comments follow a commitment by Labour north and south of the border to setting.
The education committee in Dumfries and Galloway, which is controlled by Independents, last week agreed that headteachers should be given the option of introducing setting in any subject once pupils reach their second term in the first year of secondary school.
But the move is likely to be restricted to mathematics and English classes because of timetabling difficulties and is unlikely to have much impact in the council's smaller rural secondaries.
The authority and heads say the policy merely recognises the reality in schools. Fraser Sanderson, senior official responsible for the change, said the impetus came from heads who complained of gaps in the 5-14 programme and lack of preparation for Standard grade.
Mr Sanderson said existing arrangements for mixed-ability teaching were holding back more able pupils and preventing learning support staff targeting those who needed more help.
He stated: "We have quite a lot of youngsters working beyond level E and outwith the curricular framework. There is a lot of fast-tracking that goes on around the country." There was no overall threat to mixed ability teaching and the vast majority of classes would retain a broad range of pupil ability.
However, Professor Boyd, a key researcher on differentiation within the 5-14 programme, said the move was "retrograde" and "an organisational response to a learning and teaching problem". Mixed-ability teaching was being blamed for problems that lay elsewhere and had a "very good record" in contributing to rising success rates at Standard grade and Higher.
Professor Boyd told The TES Scotland: "Any decision needs to be based on a clear rationale and I do not think there is one. There is no piece of research evidence which shows that youngsters learn more effectively in set groups. " The danger was that many young people would be labelled as underperformers. Even for the most able pupils there was "no one way to organise learning".
Colin Mitchell, head of Dumfries High and a spokesman for the Headteachers' Association of Scotland, said more schools were looking at setting and broad banding and his own school had experimented in setting in mathematics in secondary 2 with some success. Budget cuts had also reduced staffing levels and forced the school to re-examine mixed-ability teaching as class sizes crept up.
"We believe in mixed-ability teaching and it is not a major issue because people are experimenting anyway. We are anti-streaming and this is not the thin end of the wedge," Mr Mitchell said.
Since setting was introduced, the number of classes for the more able has increased while those for the less able have decreased, Mr Mitchell said. Pupils could go up or down according to their progress.