Plans to have pupils start primary schooling a year later at age six are being actively considered by cash-strapped local authorities in Scotland, according to a leading education figure.

The move would involve three years of nursery education instead of two, and six years of primary education instead of seven.

It was also revealed that consideration was being given to a change in hours at secondary schools to a 10am start, to suit the body clocks of adolescents.

The current thinking of a number of councils was revealed yesterday by John Stodter, general secretary of the Association of Directors of Education in Scotland.

He was responding to a call from Education Secretary Michael Russell for councils to come up with "imaginative ideas" to make improvements to their service in exchange for the freedom to cut teacher numbers.

Increasing the school starting age to six, more shared services between local authorities and sending pupils to "hub" schools for certain lessons were among the ideas floated by council representatives at Holyrood's Education Committee.

Unions last night accused councils of pursuing the plans for cost-cutting purposes, but speaking to The Herald, Mr Stodter insisted a move towards primary children starting at age six would only be done on the grounds that pupils were not disadvantaged.

Mr Russell made clear he remains convinced about the link between teacher numbers and attainment, while council representatives insisted the "jury was out" on that direct connection. The minister has suspended sanctions on councils who want to cut teachers in exchange for them coming forward with fresh thinking on reforms.

Mr Stodter told MSPs: "There are two things that need to happen before we get into the detail of what the ideas might be. One is an agreement from politicians - the Government, MSPs and Cosla - that we can look at the whole system of the learner journey from early years to 18 and beyond.

"We would then need discussions about specific ideas and what these might mean. These should work in a way that shows that, one; there is clearly an educational advantage and benefit that improves it and, two; that it is more efficient and that there may be a financial saving it.

"The third element would be that we have to ensure that no-one is disadvantaged by it. I'm not suggesting this, but people have talked about the age at which children start school. Some schools and authorities say that six-years-old could be a better time to start school education."

He said if that were to be educationally proven then local authorities would have to ensure that families weren't disadvantaged by that process, and that they had a system that could support children starting at six and they were confident that it was going to lead to improvements.

Mr Russell told MSPs: "Let me make it absolutely clear: I don't believe you can drive up attainment and improve outcomes with fewer teachers.

"We are, of course, committed to working with local government, with the engagement of parents and trade unions, in seeking to reach an agreement on better educational outcomes and what those might be. There is strong argument for imagining and putting in place better ways of delivering, for example, shared services and issues of that nature"

Mr Russell added: "If there is no agreement on outcomes, then the sanctions will continue. They haven't been lifted, but they are not going to be operated while we have this discussion."

Such a change would in effect create a third year of nursery education and a cut from seven to six in the number of years of primary schooling. That might be attractive on financial grounds given the relative cost of primary teachers to nursery assistants.

The Educational Institute of Scotland said: "It is deeply concerning that local authorities might seek to abuse the notion of starting school later as a pure cost-cutting measure.

"While some education systems are based on models where pupils start formal schooling later, this tends to occur in countries where overall level of educational investment is actually significantly higher, per pupil, than it is in Scotland. In short, starting school later is not, and never should be seen, as desirable as a cost-cutting measure."

Cosla education spokesman Douglas Chapman said: "Whether there is a direct link between a fall in teacher numbers and maintaining the level of attainment you want to see or improvement in attainment, I think the jury is out on that one but nevertheless it would have an impact in terms of teachers, I'm sure."