The new limits will apply to primary 1 classes from August, to primary 2 from August next year and to primary 3 from August 2001. The Scottish Office says the number of pupils at these stages who are being educated in classes that exceed 30 has already fallen by more than 5,000 in the year to last September.
The regulations set out categories of "excepted pupils" who can be enrolled even if the class limits are breached, although this will mainly be valid only for the year they join the class. This is designed to protect parental choice and pupils with special educational needs.
The new regulations also allow for exceptions where limits on class size "would prejudice efficient education or the efficient use of resources".