Labour has raised concerns about a 40% increase in the number of primary pupils being taught in classes of 30 or more.

In 2016, the pupil census showed that 44,667 (11%) of Scotland's 396,697 primary pupils were in a class of more than 30.

That compares to 31,842 (9%) of the 366,429 pupils in 2011.

Labour said the figures underlined the need to use the Scottish Parliament's income tax powers to invest more in education.

Education spokesman Iain Gray MSP said: "The SNP came to power promising to cut classroom sizes - instead it has just cut the number of teachers in our schools.

"Promises, pledges and PR stunts on education cannot hide the SNP's dismal record on our schools - 4,000 fewer teachers, £1.5 billion cut from local budgets, super-sized school classes and a stubborn attainment gap between the richest and the rest."

Mr Gray highlighted comments made earlier this week by EIS president Nicola Fisher at the SNP's conference in Glasgow that teachers were ''on their knees'', with low pay and high workloads taking a toll on mental, physical and emotional health.

He said: "Not only has the SNP betrayed parents and pupils with this broken promise - it is one of the reasons John Swinney was told to his face at the SNP conference that Scottish teachers are 'on their knees'.

"Just as ten years of the SNP has left Scottish teachers among the lowest paid and most overworked in the developed world, they have also delivered some of the biggest class sizes in the world in Scottish schools.

"Nicola Sturgeon put her top minister in charge of the education brief - but John Swinney has found himself overwhelmed and is unable to explain how his misguided reforms will cut class sizes."

A Scottish Government spokesman said: "In 2010, we legislated to reduce the maximum class size in primary one to 25, its lowest-ever level.

"Since then, the number of P1 pupils in a class size of 26 or more has decreased by 90% from 6,896 in 2010 to 698 in 2016.

"We are reforming the education system to close the poverty-related attainment gap and target resources at the children, schools and communities which most need them.

"We are investing £88 million this year so every school has access to the right number of teachers and securing places for all probationers who want them.

"Our investment has enabled councils to maintain the pupil-teacher ratio and halted a period of steady decline in teacher recruitment, resulting in 253 more teachers last year - the first substantial increase since 2007."