The Blockhouse

The Blockhouse is a structure located in Tresco, likely built between 1548 and 1552. It is made of roughly coursed granite rubble and has a rectangular plan. The top of the platform is surrounded by walls that were originally topped with a parapet featuring embrasures. There are stairs on the east side, and a winder staircase leads to an original lean-to in the south-east corner, which includes a plain granite open fireplace. There are also remains of a later room constructed in the south-east corner of the platform. The Blockhouse overlooks Old Grimsby Harbour and is believed to be one of the blockhouses built on Tresco under Sir Francis Fleming and later John Kiligrew, captain of Pendennis Castle. The site is scheduled as an Ancient Monument.