Harry's Walls, ruins in Isles of Scilly

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What is recorded here

Harry's Walls are the unfinished remains of an advanced artillery fort ordered by Edward VI's government in 1551 to defend Hugh Town harbour from France. Planned with Italian-style bastions, it was abandoned as money ran short and the invasion danger passed.

Who built and held it

Captain John Killigrew of Pendennis Castle was ordered to build the fort on St Mary's after Thomas Seymour inspected the Isles of Scilly. The Crown intended a square garrison fort with four angular bastions, living quarters, a mill and a brewhouse.

Attack, change and use

Two small guns were installed, but the fort never faced attack and was never completed. Later governments chose Star Castle instead; rubbish was dumped among the abandoned walls, and eighteenth-century visitors blamed the site before modern research showed it covered the harbour effectively.

What survives

Two granite bastions, their protective orillons, a connecting curtain wall and part of an unfinished ditch survive on the south-west side. Stone robbing exposed the rubble core, but the remaining plan still shows the intended new style of defence.

Why it mattered

Had it been finished, Harry's Walls would have been the most advanced fort design then in England. Its abandonment records the financial limits of Edward VI's defensive programme and the moment Italian artillery ideas were reaching English shores.