CONGREGATIONS within Scotland's Catholic heartlands have been given details of the first steps of a major overhaul expected to see significant numbers of parish closures.

The Archdiocese of Glasgow, home to by far the largest number of the country's Catholics, has published details of 'clusters', essentially groups of around four or five churches in close proximity to each other to be brought together amid falling numbers of priests and parishioners.

Over the next three years parishes will be expected to pull resources on matters from community groups and social events to service times.

Although the Archdiocese insists there is 'no presumption of closure', a large number are expected to shut their doors in the years ahead.

One source said: "Clustering parishes together spreads out the responsibilities, for example ensuring two parishes in close proximity aren't both having mass at 9am on a Sunday.

"It encourages folk to get used to going to different churches so when the time comes it's not such a massive shock if their parish shuts. It also makes sure any closures are staggered over a longer period of time."

The decision to come up with 22 parish clusters across the Archdiocese comes on the back of nearly two years of discussions with local congregations. A number of clusters include either high-profile or well-attended parishes with those under most threat obvious to those who attend.

Although the last census recorded the number of Catholics has risen since 2001, crucially many are moving home, leaving empty churches in some areas and full and even expanding ones in others.

Congregations are shrinking in council schemes built in the 1950s and 1960s and now being redeveloped.

Those in suburbs, near good Catholic schools, such St Ninian's in Giffnock, are thriving. However, between 1991 and 2012 there were drops of 41 per cent for mass attendances, 39 per cent for baptisms, 54 per cent for marriages and 14 per cent for funerals.

The Herald previously published figures showing the archdiocese expects to have just 45 priests within two decades, enough for fewer than half its current parishes.

A spokesman for the Archdiocese said: "For the next three years there will be a programme to assist collaboration among the parishes of each cluster, involving jointly planned spiritual and social events, sharing expertise, co-ordinating times of services and so on.

"Only at the end of this period will we be in a position to develop a long-term strategy for the provision of parishes and to decide if, when, or where there is a need for merger or closure.

"Such decisions will be taken ultimately only after canonical due process involving thorough consultation."

The Archdiocese also denied it was attempting to create 'super-parishes' and that only in some circumstances would formal amalgamations be an option, while some within the church have accused the hierarchy of procrastination and seeking to avoid any conflict at all costs.