The other four historic buildings are expected to stop hosting mass on a regular basis within the next 10 years as part of a massive overhaul of city churches.

The Diocese of Lancaster has launched a study into the six churches to decide which should stay open – and what to do with those which are to close.

This will look at the churches of St Walburge's in Pedder Street, Ashton, English Martyrs in Garstang Road, St Ignatius off Ring Way, St Augustine's in Avenham, St Joseph's in Ribbleton Lane and St Wilfrid's near Winckley Square.

A letter from the Bishop was read out at mass in all affected churches on Sunday. It is expected that St Ignatius will be one of the buildings saved from the axe – leaving five others to fight for survival.

The news follows the 18-month Fit for Mission? review of churches in the Diocese which has recommended closing 10 churches through Preston in a money-saving exercise.

Bishop of Lancaster Patrick O'Donoghue said consultants from the London-based Architectural History Practice (AHP) would be carrying out a study of the buildings until November.

He said: "I welcome the contribution the AHP will make to our specific assessment of the future use of these magnificent church buildings that hold a special place in the hearts not only of Roman Catholics, but also the wider community."

In a statement, the Diocese said: "The study will assess the architectural value of all the churches in order to inform decisions about which ones should be secured, how this might be done and what other uses might be appropriate for some. Bishop O'Donoghue is aware that it is likely only two inner-city churches would be necessary for pastoral purposes."

Coun Margaret McManus, a member of Preston Council and a worshipper at the iconic St Walburge's Church, said it was "unthinkable" that it would be closed for worship.

She said: "We have to wait in November for the Bishop to make his decision on the final proposals of the Mission Review, I am just praying it will not happen."