Average class sizes in P1-3 have gone up marginally - from 22.5 in 2011 to 22.6 in 2012, this year’s schools census shows.

And the percentage of pupils in classes of 18 or fewer - a key SNP manifesto target - has dropped from 20.1 per cent to 18.8 per cent.

But education secretary Michael Russell this week credited the class-size figures for P1 to the government’s decision to legislate on the issue.

It was now considering extending the legislation to cover P2 and P3 and introducing a clearer definition of “access to a teacher” for pre-school children, he told TESS.

“Despite pupil numbers increasing, we have almost wiped out P1 classes of more than 25 - the number of P1 children in these classes has fallen by 97 per cent since 2006 and we have made clear progress since introducing legislation,” he said.

EIS general secretary Larry Flanagan welcomed statistics showing that the target agreed by the Scottish Negotiating Committee for Teachers for a minimum number of teachers of 51,131 had again been met.

But he warned that with 12 per cent of teachers on temporary contracts, lack of job security might drive some out of the profession.