St Mary's Church lies within a polygonal churchyard, part of whose western boundary is delineated by a stream, which rises from a well at the point where the road diverges from the churchyard boundary. The well has a circular, stone-lined chamber that has been surrounded by a stone wall capped with concrete and covered with an iron grill. The churchyard occupies a prominent hilltop location on an east to west ridge, crossed by a ridgeway which may be prehistoric in origin and form the primary axis of an enclosed, co-axial field system. Warren parish boundary, and the boundary of the adjacent parish of St Twynnells, follow the co-axial field system boundaries. St Twynell's Church (NPRN 400352) and St Mary's are approximately equidistant from Castle Park defended enclosure (NPRN 305419) and it is thought that the two parishes may perpetuate prehistoric land units that related to the Iron Age site. This indicates early medieval origins for the church site. Around the end of the 13th century the Bishops of St Davids leased the church to William Harold of Haroldstone. The lease passed to the Perrot family through marriage. The church currently lies on the edge of the Castlemartin firing range and is under ecumenical ownership under the auspices of the MOD. A wheel cross (NPRN 305418), constructed since 1886, sits upon a square, three-stepped cross base which may be medieval.

The current building is thought to date to the 13th century. It consists of nave, chancel, south transept and tower. The rood screen corbels are still in situ on the west face of the chancel arch. The north aisle was removed in 1770, reportedly by Mr Abraham Leach, whose father held the grand tithe and was responsible for repairs. The church was restored in 1855, to the designs of David Brandon of London. The work was commissioned by Lord Cawdor. A new chancel, chancel arch and arch to the south transept were constructed, and the church was refenestrated. New floors were laid, incorporating Minton tiles carrying the coat of arms of Lord Cawdor and the Bishop of St David's in the Chancel. At that time war with France seemed imminent and fortifications were being constructed around Milford Haven and along the South Pembrokeshire coast. As a prominent landmark, the church tower was chosen by the Admiralty for enhancement as an unmistakable landmark for passing ships. The tower's ivy-covered and perished stonework was encased in Forest of Dean stone. Its spire, originally made of wood, was considered unsafe and replaced with the help of the Admiralty. The church fell into disrepair and was closed by the diocese in 1970. In 1986 it was decided that there was a need for a multidenominational place of worship for the thousands of British and German troops passing through the Castlemartin range. The Warren Church Trust was formed and the church was restored in 1986-1988, to the designs of Michell & Holden, Pembroke. The church reopened in 1988 and the opening service was taken by the Archbishop of Wales. The service was attended by the Chaplain General to the Army, Anglican, Catholic and Lutheran clerics from UK and Germany and the Defence Attache from the German Embassy in London. The recently restored roof was blown off the church during a hurricane in 1990, and had to be replaced. Displayed on the nave's north wall are the flags of the countries associated with the Church (England, Germany and Wales) and two display boards containing the regimental badges of the regiments who have used the range. The altar table and font cover were made by the staff of the German artillery ranges at Bergen, from oak trees on the training area, and donated by the Ministry of Defence, Federal Republic of Germany.

Sources include:
Cambria Archaeology, 2003, Early Medieval Ecclesiastical Sites Project, Pembrokeshire gazetteer
Dyfed Archaeological Trust, Historic Environment Record
St Mary's Church Warren, warren-church.org.uk


N Vousden, 26 November 2018