Calls have been made for an urgent review of the way school reorganisations are handled after the controversial rejection of a proposal by the Assembly government.
The Welsh Local Government Association (WLGA) called the first minister's decision to reject Cardiff City Council's plans "retrograde and questionable", while the Conservatives said it set a "worrying precedent".
Cardiff had planned to close the English-medium Lansdowne Primary School to make way for the expansion of Welsh-medium Ysgol Treganna, which has outgrown its current site. Pupils would have moved into an expanded Radnor Primary School, which shares its site with Ysgol Treganna.
But first minister Carwyn Jones said the plans were unlikely to improve education provision in the area, and would not ensure a "broad and balanced" curriculum because of the size constraints of the Radnor site.
The shock decision has raised serious concerns about school reorganisations across Wales, which are usually rubber-stamped by the Assembly government with the minimum of fuss. All local authorities have been encouraged to rationalise their provision to tackle surplus places and get value for money.
Many are also reorganising to deal with an upsurge in the parental demand for Welsh-medium education, as in Cardiff. But there is concern that the process is taking too long, a fact recently acknowledged by education minister Leighton Andrews.
Figures obtained by the Liberal Democrats show that ten of the most recent ministerial decisions were issued an average of 42 weeks after proposals were published. Now there is anger that the Lansdowne decision has taken more than nine months.
Rodney Berman, Cardiff City Council's leader, called for an urgent review of the process: "If schools reorganisation is now a political football, other local authorities may now be reluctant to put forward their proposals because none of us know what the ground rules are any more."
His views were backed by the WLGA, which said the decision exposed the "yawning gap" between "national rhetoric and local reality" on the issue of surplus places.
Peter Fox, the WLGA's education spokesman, said: "The rejection calls into sharp relief the question of meaningful shared commitment at government level."
Paul Davies, the shadow education minister, said the government's actions would call into question the ability of local authorities to make similar decisions in future.
Dr Philip Dixon, director of the Association of Teachers and Lecturers Cymru, said: "It seems odd that we have encouraged local authorities to rationalise their education provision but then the government says this is a rationalisation too far."
The Assembly government said: "It is now for the local authority to look at alternative proposals as a matter of urgency."