Scottish primary school classes are among the biggest in the developed world, it has been reported.
The average class size has risen to 23.5 in the past year - the highest since SNP took over in 2007.
Scottish Conservative education spokeswoman, Liz Smith, said: “The SNP made a very firm commitment in its 2007 manifesto to deliver class sizes in P1-P3 of 18 or fewer.
“That never happened, so they changed the goalposts to ensure pupil/teacher ratios were improved - that policy didn’t work either.
“Now we find out that as well as Scotland lagging behind international results, we are also lagging behind other countries in these key measurements.”
The average primary class size has risen from 23.4 to 23.5 in the past year.
The average for countries in the Organisation for Economic Co-operation and Development (more commonly referred to as developed countries) is 21.
Larry Flanagan, general secretary of the Educational Institute of Scotland said: “It is disappointing the Scottish Government, which stood ten years ago on a platform of reducing class sizes has not yet delivered smaller classes for the majority of Scotland’s pupils.
“Smaller classes can be particularly beneficial when working with pupils in areas of deprivation, currently a key focus of the Scottish Government.”
A Scottish Government spokesman said: “We have committed an £88 million package of funding for local authorities to maintain pupil teacher ratios at 2015 levels in 2016-17 and secure places for all probationers who want them.”