Old Blockhouse

The Old Blockhouse stands above Old Grimsby harbour on Tresco, a small artillery fort built between 1548 and 1554 to defend the island's eastern approach. Its substantial stone remains recall a wider programme of Tudor fortification across Scilly, followed by fighting when Parliamentarian forces attacked the Royalist islands in 1651. Climbing into the ruin gives a clear sense of its defensive position over the beach and sea, although its guns proved less effective against longer-range naval weapons. Reviewers especially value the panoramic views and opportunities for coastal photography. English Heritage describes a twenty-minute walk from Old Grimsby along island lanes; boat travel to Tresco must be arranged separately. The final entrance has steep, uneven steps and there are unguarded drops inside, so supervise children closely and wear secure footwear. Dogs on leads are welcome. Allow time to enjoy the setting as well as the compact fort itself.