The demolition of one of Dublin’s biggest Catholic churches, and its replacement with a new place of worship only a tenth of the size, has been approved by Dublin City Council.

The Church of the Annunciation in Finglas West was built in the late 1960s for a capacity of almost 3,500 parishioners, during a church-building boom initiated by the then archbishop of Dublin, John Charles McQuaid.

The new church will seat just over 300, with the residual land to be used for senior citizens’ housing. However, documents show the parish also plans to sell a neighbouring site of almost six acres, which is several times larger than the church site, to Dublin City Council.

The larger site, known as St Fergal’s Field, is sandwiched between three schools. The council had initially hoped to use the field for housing, but is now in negotiations with the Health Service Executive to use the land for a primary care centre.

A map showin the current church to be demolish (top left) and the new site surrounded by three schools. Final Mass Archbishop of Dublin Diarmuid Martin celebrated the final Mass in the Church in October 2018, and an application was lodged with the council the following May for the demolition of the building and the construction of the new, small church and a parish centre.

However, the decision to grant permission for the work took more than eight months, following concerns raised by the council planners over the future use of the residual church lands.

In a letter to the parish, planners said the application had included “sparse information in relation to the intended future use of the remaining part of the site” that would not be required for the new, smaller church.

“The development description and accompanying planning report both state that the residual site area will be the subject of a separate future application, and the architectural design statement states that this area will be used for the development of accommodation for senior citizens, although no further information is provided.”

The final Mass at the Church of the Annunciation in Finglas West in October 2018, celebrated by Archbishop of Dublin Diarmuid Martin. Photograph: Nick Bradshaw for The Irish Times ‘Open space’ The letter also makes reference to St Fergal’s Field and how “the retention of existing functional open space, eg school playing fields” would be addressed.

The parish owns St Brigid’s, a girls’ primary school to the south of the field, and St Fergal’s Boys National School to the north. Coláiste Eoin, a post-primary school not owned by the parish, is also immediately north of the field.

In response to the planners, the parish said the field had been “derelict for several years and is subject to anti-social behaviour”.

A letter attached to the response confirms representatives of the parish “are in advanced negotiations” with the council to buy both the surplus church lands and St Fergal’s Field.