The proportion of P1-3 pupils being taught in classes of 26 or more has increased, new Scottish figures have revealed.
National statistics showed that, in the last school year, 26.3 per cent of pupils in the first three years of primary – 44,712 in total – were being taught in class of at least 26.
The Scottish government, however, welcomed other new figures which showed rises in overall teacher number and in school support staff for pupils with additional needs.
The class-sizes figures come despite the Scottish government's longstanding "aspiration" of reducing class sizes for youngsters in P1-3 to 18 pupils or less, which goes back to long before the SNP came into power in 2007. The issue of class sizes has, however, become less prominent in successive election manifestos.
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The figure is up from 26.1 per cent of P1-3 pupils in 2017, and compares to the 38,278 P1-3s taught in classes of 26 or more in 2012.
The figures also showed that the number of P1-3 children taught in a class of 18 pupils or fewer has fallen to 20,613, or 12.1 per cent of pupils in that group, down from 20,997 the previous year.
The Scottish Liberal Democrats highlighted figures showing that 43,193 primary schools pupils were being taught in classes made up of 31 or more students, up from 31,175 in 2012.
Lib Dem education spokesman Tavish Scott said: "The number of pupils being taught in super-size classes has soared on the SNP's watch.
"Classes of this size make it harder to close the attainment gap. Smaller classes help pupils learn and increases the amount of contact time between teachers and those children who need extra help."
Scottish government statistics also showed that in 2018 there were 511 P1 pupils being taught in a class with more than 25 students, despite 2010 legislation to limit class sizes for P1 to a maximum of 25. That, however, was an improvement on the 2017 figure of 631.
Scotland had 2,483 schools in 2018, with a total of 693,251 pupils, including 400,276 at primary school.
The average class size in primary schools last year was 23.5 – the same as 2016 and 2017, but higher than in 2012, when it was 22.7.
On average, P1-3 classes had 23.2 pupils, while across the country the proportion taught in a class of 18 or fewer varied from 56.4 per cent in the Western Isles to 3.1 per cent in Dundee.
The new figures also showed an increase in the number of teachers working in Scotland's schools, from 51,513 in 2017 to 51,959 last year.
The number of school staff supporting pupils with additional needs rose by 7.7 per cent over the year, to 14,547.
Education secretary John Swinney said: "While all teachers work with pupils with additional support needs, I welcome the increase in specialist staff which shows education authorities are continuing to invest in having the right support, in the right place, to meet young people's needs.
"The latest data also shows that, overall, teacher numbers in Scottish schools are at their highest since 2010, with primary teacher numbers at the highest level since 1980."