Plans for new glazing at a medieval Pembrokeshire church of ‘exceptional interest’ have been submitted to the National Park.

The listed building consent application to the Pembrokeshire Coast National Park Authority by Rachel Morley of Friends of Friendless Churches sought permission for the reglazing of the west window in the north aisle of the Grade-I-listed St Michaels Church, Church Lane, Castlemartin.

A supporting statement through agent Andrew Faulkner Associates Ltd describes St Micheals, which includes a 12th century font, as “a fine large rural medieval church (late 12th century) with an ancient history and much adaptation, particularly to the tower and east end”.

It goes on to say: “The north and south chapels, and the north transept, were removed in the fifteenth centuries. The 1858 restoration (David Brandon, commissioned by John Campbell, Earl of Cawdor) saw the church re-roofed, refloored (including the encaustic tiles in the chancel – with the Cawdor Arms in decoration) and refenestrated. It is from and after this period that most of the current leaded light glazing was introduced.

“The church houses a good collection of leaded light windows including the east window (depicting the ascension, by Heaton, Butler and Payne), the slype window (depicting St Michael, possibly also by Heaton, Butler and Payne, around 1900) and the south transept (Crucifixion, designed by Pugin – the only surviving Pugin window in any Welsh church – and the last remaining window made by Hard, one of five originally installed in the church) Pugin. Other windows are more ordinary 19th century work of strongly C19th character.”

It adds: “Overall, the building is in good structural order and benefits hugely from having had all of the main roofs relaid in recent decades. Recent repairs have seen improvements to the condition of the walls and the significant leaded light windows.

“Future repair programmes intend to continue this work, address localised leaks and problems associated with the walls and roof of the tower.

“The church is an important rural ecclesiastical building or medieval origin containing important elements of fabric and fittings. Listed at Grade I it is considered to be a particularly important building of ‘exceptional interest’.”

On the works proposed, it says: “While the church has a fine collection of leaded lights and painted glass (including the only window in Wales designed by Pugin), the west window of the north aisle is made of large sheets of modern plate glass, with rusty ferramenta, and in poor condition.”

The application will be considered at a later date.