The Church on Wednesday took the unprecedented step of petitioning the senior civil court in Scotland to overturn the refusal of Peter Peacock, Education Minister, to intervene in the row over joint campus schools in North Lanarkshire.
The authority was due this week to agree a pound;150 million contract with construction firm Balfour Beatty, but plans are now likely to be delayed.
Bishop Joe Devine, leader of the Motherwell diocese and president of the Catholic Education Commission, asked the minister in July to stop North Lanarkshire's plans. It has accepted six schemes for shared sites with non-denominational schools but is holding out for the continuation of a separate Catholic school at St Aloysius primary in the appropriately named Chapelhall area of Airdrie.
Mr Peacock said that Catholic education was not damaged by the plans but Bishop Devine told Catholic primary heads at their conference last month that he was amazed by the verdict.
The 1918 Act, he said, made clear that the local authority must run Catholic schools "in the interests of the Church" and, secondly, that there was a significant dimunition in provision caused by North Lanarkshire's insistence on shared premises at Chapelhall.
The bishop last week highlighted what he believes is Mr Peacock's error in a letter to the diocese: "In effect, by choosing not to intervene, the net result is that a local authority has the right to determine what is meant by a Catholic school. That cannot possibly be the correct conclusion."
On Wednesday, he said that he had "no alternative" but to seek a judicial review under section 22D of the Education (Scotland) Act 1980. North Lanarkshire's insistence on a joint campus at Chapelhall made it inevitable. The Church argues that with more than 300 pupils, St Aloysius is a viable school and has no need of shared premises with the much smaller Chapelhall primary.
The council late last week submitted to the Church a revised set of what it believed were conciliatory proposals but refused to give ground at Chapelhall, instead proposing to relocate the staffroom. But the Church continues to believe that the Chapelhall proposals set` "a potentially worrying national precedent".
It is vigorously opposing what it regards as a backdoor to integrated schooling and is well aware that other authorities are watching the outcome of an unseemly battle which both sides would prefer to have resolved locally.
Pressure increased last weekend after Bishop Devine had statements read out in churches attacking the authority's plans. He feared an erosion of Catholic education in the name of "community harmonisation".
Michael O'Neill, education director, was then given permission to argue the case for joint campuses in a four-page letter to all headteachers rebutting arguments put up by the Church.
This was followed by a fresh appeal to the Church from Jim McCabe, the council leader, in which Mr McCabe conceded that there would be no further joint campus proposals, "except in exceptional circumstances", until an evaluation had been carried out at the seven primaries due to share premises.
A working party involving the Church and local authority would be established to monitor progress and advise headteachers on managing joint premises.
Other concessions involved changes to entrances and improved signs. This was not enough for the Church.