The massive tower at Bosbury stands separately from the church: this is an unusual feature  and thought to be a defensive fortification.   It was built in about 1230-1240 and is one of seven such towers in Herefordshire.  Some were built to carry bells; Bosbury’s, with its thick walls and narrow windows, appears to have been built as a refuge during Welsh incursions.  Similar towers, known as pele towers, can be found in the Scottish Marches and the North of England.

The tower is 8.8 m (29 feet) square and 14.6 m (48 feet) high to the top of the parapet wall, and its walls are nearly 1.8 m (6 feet) thick at the lowest level. Originally the tower had a spire, which was struck by lightening in 1638 and replaced with the present pitched roof and weather vane in 1812

The main entrance door has recently been replaced to provide better protection from wind and weather.  The previous door has been preserved in the church along the north wall and is a fine example of the skills of craftsman of previous times.