Rufus Castle, also known as Bow and Arrow Castle, is a partially ruined castle overlooking Church Ope Cove on Portland, England. Its name derives from King William II, known as William Rufus, for whom the original castle was built.
The existing structure dates largely from the late 15th century, making it Portland's oldest castle. Built on a pinnacle of rock, some of the original structure has been lost to erosion and collapse over the years.
The remaining castle appears to have been the keep of a stronghold, the foundation of which was much above the top of the church tower of St Andrews which lay in the valley below.
Wikipedia https://en.wikipedia.org/wiki/Rufus_Castle
Coordinates 50°32'22.357" N -2°25'41.772" E