A scheme for works at one of a Pembrokeshire town’s surviving medieval churches by its neighbouring owner has been submitted to county planners.

In an application before Pembrokeshire County Council, Stefan Smart seeks permission for a change of use of the disused Grade-II-listed St Thomas A Becket Chapel, The Rath, Milford Haven to provide an ancillary use for an adjacent dwelling.

It includes the installation of suspended floor over original flagstone flooring to preserve and protect it, and the addition of a first floor to be bolted to the existing stone walls.

A supporting statement by agent Heath Coombe Architecture details the history of The Church of St Thomas A, originally built in 1180 and dedicated to St Thomas Becket, which was also utilised as a Beacon Chapel or lighthouse to sailors.

It says the chapel was closely linked to the nearby Pill Priory, and fell into ruin by the 17th century, and was occupied by parliamentarian forces in 1644.

By the 20th century it had fallen to use as a pigsty and stable, before £1,000 was raised in 1930 for its restoration, completed in 1938 when it was reinstated as an Anglican chapel of ease.

In 2012 the property, set back behind The Rath, was privately purchased, with the owner continuing to maintain the building, to ensure its continued survival, the statement says.

It adds: “The Church of St Thomas Becket remains medieval in style, and is the last of the three medieval churches to have survived in Milford Haven.

“The proposal has been subject to consultation to ensure it not only meets the owner’s future needs but also, by involving the local authority conservation officer through the design process, the proposal should not detract from the listed building status.”

The application will be considered by county planners at a later date.