Weekend reports that this option was gaining ground were firmly dismissed by Michael McGrath, director of the Scottish Catholic Education Service.
The reports followed the latest apparent breakdown in discussions between the Church and North Lanarkshire Council over the authority's plans to build seven shared-campus primaries as part of a pound;150 million public private partnership (PPP) renovation programme for schools.
Bishop Joseph Devine of Motherwell, believed to be under considerable pressure from local activists, has now taken the unprecedented step of asking the First Minister to give the matter his "urgent personal attention".
A spokesperson for Jack McConnell, no stranger to the issues as a North Lanarkshire MSP, said he would reply in due course, "having considered the concerns raised". Meantime, Mr McConnell encouraged both sides "to continue their dialogue".
Bishop Devine, who is also president of the Catholic Education Commission, raised his objections "with regret" on the basis of fears that the council's plans would lead to a "serious deterioration" in the provision of Catholic education in the schools involved, under section 22D of the Education (Scotland) Act 1980.
In his letter to Mr McConnell, Bishop Devine stated: "In all seven communities, I fail to be convinced that, in these proposals, the council will be conducting these Catholic schools 'in the interests of' the Roman Catholic Church, as is required of them by the Act."
The diocese of Motherwell had accepted the principle of shared campuses in six of the linked schools. It has strongly opposed plans for the seventh, involving St Aloysius' primary in Chapelhall, Airdrie, on the grounds that the school was viable on its own with more than 300 pupils.
Bishop Devine, who was quoted in recent weeks as saying discussions were "about four-fifths of the way there", now says he has "become increasingly concerned that the council was seeking to maximise the provision of shared facilities, to the detriment of the distinctive identity and education which should be provided by each school community".
He said he could only approve proposals that meet guidelines laid down by the Bishop's Conference of Scotland. But Jim McCabe, leader of North Lanarkshire Council, said its plans followed guidelines from the Catholic Education Commission.
Mr McCabe said meetings with Church representatives had led to significant detailed design changes and, in two cases, had resulted in completely new designs. He felt these discussions were very constructive and he now found himself "bemused and disappointed and genuinely surprised".
Charles Gray, the council's education convener, said that, far from resulting in a deterioration in Catholic education, "the plans will lead to a significant enhancement".
But Mr McGrath issued a forceful statement of Catholic values: "The Catholic school's distinctive identity should be visible throughout the school, in the quality of the relationships formed, in its culture and ethos, in its expression of values and beliefs, in various forms of display and ornamentation, in opportunities for prayer and worship, and in many other activities, as appropriate to the Christian calendar, such as celebrating important feast days and observing the seasons of lent, advent, etc.
"The Church expects that a close involvement with parents and with the local parish community, in various efforts to provide young people with adequate formation in a Christian environment, will be reflected in distinctive programmes of sacramental preparation and ongoing spiritual development in every Catholic school."
Despite what Church leaders feel is a steady encroachment on these principles, following pressure on local authorities to drive down costs under PPP, Mr McGrath said the Church "wishes to remain in the existing system".
One possible reason is that the opt-out legislation has been removed from the statute book.