More than 120 schools across Scotland are teaching pupils at least three different qualifications at the same time.

Figures obtained by the Scottish Conservatives show there are 112 schools where a subject is being taught to three different qualification levels and a further 11 schools where classes have pupils studying for four different exams.

Ruth Davidson, the Conservative Party leader, challenged Education Secretary John Swinney on the issue as he stood in for Nicola Sturgeon at First Minister's Questions at Holyrood.

READ MORE: Teachers teaching three qualifications at once

With the First Minister in Normandy for D Day commemorations, Ms Davidson told Mr Swinney that in Inverclyde Academy in Greenock "maths is being taught for National 4, National 5, Higher and Advanced Higher all in the same classroom".

The EIS teaching union has warned of an "explosion" of such classes, she added, while leaders of another trades union, the NASUWT, have complained that this causes "intolerable workload or stress" for teachers.

Ms Davidson pressed the Education Secretary on the practice of multi-level classes, saying he had he previously claimed "he had never heard anybody argue educationally there was something wrong with it".

However, John Swinney, the Education Secretary, dismissed the claims as a "moanfest".

READ MORE: Slump in standards blamed on multi-course teaching

He accepted there was a "debate to be had" about the use of such classes, telling the Conservative leader: "There is a debate to be had about every single topic within education, education is a part of our society that is actively the subject of debate."

But he insisted multi-level teaching had been a feature of education since he was at school.

He said: "I certainly stand by my remarks that multi-level teaching is able to be delivered effectively in our schools by teachers who are trained to deliver professionalism of that quality and that standard."

Ms Davidson called on SNP ministers to "face up to the challenges in our schools, not deny that they exist".

Mr Swinney responded by arguing what matters was pupils' achievements, as he told MSPs attainment levels were rising.

READ MORE: Advanced Higher pupils 'teaching themselves'

"What I am interested in is making sure our education system delivers the best outcomes possible for the young people of Scotland," he said.

"And on that the evidence is substantial that the education system is doing exactly that.

"We see young people now achieving more within our schools, we see attainment rising within our society, equipping our young people with the qualifications they require and we also see young people leaving school to the highest level of positive destinations in our history."