PURBECK schools will change to a two-tier system from a three-tier system, a national schools adjudicator has ruled.

A decision by Dorset County Council in the summer to reorganise the system and tackle more than 1,250 spare places was subject to an appeal process.

Alan Parker, of the Office of the Schools Adjudicator, did not uphold the objection to the proposals.

Four middle schools will close as a result of the decision, while 13 first schools will be expanded into primaries.

Purbeck School will be expanded into a school for 11- to 18-year-olds.

Mr Parker’s decision letter said: “While the current system is functioning satisfactorily, there are clear signs that it could easily go into a period of rapid decline unless suitable action is taken.”

Toni Coombs, council spokeswoman for children’s services, said: “Change is hard, but we can now move forward with the reorganisation and focus on supporting pupils, staff and communities.”

The new system will be fully in place by September, 2013.