The number of hours that primary pupils in Scotland spend with a teacher is once again under threat.

This is despite the Scottish government promising in 2016 to legislate in order to ensure that primary children receive at least 25 hours a week of teacher-led lessons.

Tes Scotland  has learned that, in fact, the government has not fulfilled this promise - leaving local authorities free to cut hours.

Now, Dumfries and Galloway Council and West Lothian Council are both looking to cut the time children spend with a qualified teacher in order to save money, a move that the EIS teaching union says would be “a real cut to educational provision which should alarm parents and local taxpayers”.

Background: Scottish councils cut education spending by up to a fifth

Related: Council looking at cutting teachers to save money

Quick read: ‘Budget cuts’ impact on schools will be profound’

Dumfries and Galloway Council is exploring the possibility of covering one hour of the time teachers have out of class to prepare with someone other than a teacher. The council estimates the move would save over £1 million a year in teacher costs.

Will teaching time be cut?

In West Lothian, officials are looking at “replacing teaching time with new learning experiences and activities facilitated or supervised by advanced pupil support workers”.

This proposal would mean that all teacher preparation time - 2.5 hours per week - being covered by non-teachers. This would result in a saving of almost £3 million and lead to over 30 full-time-equivalent teaching posts disappearing, council figures show.

In 2016 two other local authorities - Renfrewshire and West Dunbartonshire - put forward similar proposals to the Scottish government, which responded by saying it would legislate in order to guarantee primary pupils 25 hours a week with a teacher.

However, Tes Scotland has learned that the pledge was never delivered and, although the government has the power to specify the number of learning hours that schools provide, it has yet to use it.

Now - as councils are beginning once again to look at how they are going to plug the black holes in their budgets - the hours that primary children get to spend with a teacher are once again under threat because they are not enshrined in law.

Scottish Labour education spokesman Iain Gray said there would be “no question of diluting children’s learning like this if SNP ministers had simply delivered on their promise to legislate to protect the primary school week”. He called on them to act and bring forward “the promised measure to protect our children’s education”.

The general secretary of the EIS teaching union, Larry Flanagan, said plans like those being considered in Dumfries and Galloway and West Lothian amounted to “a real cut to educational provision which should alarm parents and local taxpayers”. He told Tes Scotland that there was nothing wrong with pupils spending time with the likes of active school coordinators but that should be over and above the time they spent with teachers.

He added: “In the past wherever there has been any suggestion that a council would cut the length of the primary pupil week as a cost-saving measure, the EIS and parent groups have resisted this fiercely and we would do so again.

“On the last occasion when this arose, the response of Scottish government was to consider legislation to enforce the 25 hours as a statutory requirement. The EIS would expect it to enact that promise if it becomes necessary.”

As the law stands, councils have to open schools for 190 days a year but the length and structure of the school day is not specified in legislation.

The Scottish government promised to change all that by making a minimum number of hours per week a statutory requirement.

It said primary school children would be guaranteed at least 950 hours a year of teaching time, equivalent to 25 hours a week. But the requirement was never put into law.

A Scottish government spokesperson said: “It is for local authorities to make decisions about the learning hours provided but these should be based on the educational benefit to pupils rather than to reduce costs.”

A spokesman for council umbrella body Cosla said: “All councils are making difficult decisions in as they seek to make significant savings in the face of reducing budgets. At the same time, they will be focused on ensuring that they meet their statutory duties across the range of services they provide. Cosla are seeking a fair settlement from the Scottish government and we will continue to press for this to make sure all of our services are fully funded.”

Research in 2015 by Reform Scotland found that pupils could receive over a year more of teaching time over the course of their time in primary, depending on which council they were in.

At that time, the think tank found that Aberdeenshire Council and West Dunbartonshire Council offered the most teaching time in Scotland, with 1,000 hours per year in primary school. Moray offered the least, at 851 hours.