Fiona Hyslop has hit back at criticism of her failure to deliver on the SNP's pledge to slash primary class sizes.
The Education Secretary was quizzed by Holyrood's Education Committee on Wednesday.
Her party had pledged to slash primary one to three classes to 18 pupils. However, the policy was recently dropped in favour of introducing a legal limit of 25 in primary one.
Ms Hyslop used the committee meetings to lay most of the blame for the failure of the policy on Scotland's councils.
She told MSPs "We would have had a far faster rate of reduction in class sizes had local authorities maintained teacher numbers at the level they were resourced to do so.
"What they've chosen to do is not to replace retiring teachers to reduce class sizes - and that has resulted in what I think is the most significant halt in some of the progress that could have been made."
Ms Hyslop has previously insisted that progress is being made, with class sizes and pupil-teacher ratios at an all time low.
However, Labour MSP Karen Whitefield said the Government was wrong to have promised parents that infants classes would be capped.
She said: "That was the promise you made to the people of Scotland, that's what you fought the election on. That's what you told people you would deliver and at the moment we don't have class sizes of 18 for the vast majority of Scotland's children."
Liberal Democrat MSP Margaret Smith also hit out, saying: "I think the frustration for all of us is really, I suppose, the fundamental question. When you made your promise in that manifesto, did you know that you couldn't keep it?"
Ms Hyslop insisted the policy had been realistic but accused local authorities, the recession and budget cuts for hampering progress.
