PRIMARY school tests of up to three hours long were suggested by government officials, teachers' leaders have said.

Larry Flanagan, general secretary of the Educational Institute of Scotland (EIS), said the proposal was made in discussions of new standardised national tests in literacy, numeracy and spelling.

Mr Flanagan said it was "laughable" to think pupils in primary could sit a test lasting three hours and criticised the new assessments as going "well beyond" what was necessary.

He said: "Ministers have given assurances around the nature of the tests, but there is a very big concern that this is being driven by the statisticians in the Scottish Government who are unfamiliar with what a classroom looks like and how teaching and learning takes place.

"At the last design group meeting at one point they actually suggested the numeracy tests would be three hours and we just laughed at the notion that you could get primary kids to sit a three hour assessment when you cannot get some fifth year secondary pupils to do that.

"They then suggested that could be broken down, but the bottom line is that, in any one year, if you are talking about a total of one or two hours of testing, then you are already well beyond diagnostic testing because you would be testing everything under the sun, especially with computerised tests where the response time is quicker."

The intervention came after The Herald reported concerns from the National Parent Forum of Scotland that three separate tests for primary pupils as young as five were being drawn up each lasting up to an hour long.

The forum said the proposals, which affect pupils in P1, P4, P7 and S3, were far in excess of what was acceptable and would lead to increased stress - even if the tests were split into smaller segments to make them more manageable.

However, the Scottish Government later denied primary pupils would be asked to sit individual tests that lasted an hour and insisted the impact on children would be monitored closely.

John Swinney, the new Education Secretary, said: "No child at primary school will sit an hour-long test. Ministers have no wish to return to stressful testing in Scotland's schools for our children.

"We are introducing assessments, which will be age appropriate, and will allow teachers to tailor learning for each individual child."

Last year, First Minister Nicola Sturgeon announced that standardised testing for primary and secondary pupils was to be introduced for all pupils at key stages of their school career.

The move came after the biennial Scottish Survey of Literacy found standards of reading and writing were falling despite the introduction of the Curriculum for Excellence, which was expected to raise basic standards.

Ms Sturgeon said the tests would provide a better picture of how schools across Scotland were performing which would help close the attainment gap between rich and poor.