Harry’s Walls, St Mary’s: Visiting Scilly’s Unfinished Tudor Fort
Harry’s Walls is a free, unfinished Tudor fort on a hill above St Mary’s harbour. Here’s where to find it, how to get there, what to look for and why it was never completed.
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Harry's Walls is a free Tudor fort on a low hill just outside Hugh Town on St Mary's. It sits on Mount Flagon, high above the harbour at St Mary's Pool. It is easy to miss. Those who climb up get one of the best harbour views on Scilly, plus the story of a fort that was never finished.
Despite the name, Henry VIII never built it. Work began in 1551 under his son, Edward VI, according to English Heritage. Only one wall and two corners were done before the builders gave up. This guide covers where it is, how to get there, what to look for and what else is nearby.
Key Takeaways
- Free entry at any reasonable time in daylight. The site is cared for by English Heritage.
- Begun in 1551 under Edward VI, not Henry VIII, and never finished.
- About 0.4 km north east of Hugh Town, reached by a short uphill footpath.
- One of the first Italian style bastioned forts in England, with a Bronze Age standing stone beside it.
- No facilities on site. Toilets, shops and cafés are back in Hugh Town.
Where Is Harry's Walls?
Harry's Walls stands on Mount Flagon, a small hill on the west side of St Mary's. It looks down over St Mary's Pool, the island's main harbour, close to Porthloo. English Heritage puts it 0.25 miles (0.4 km) north east of Hugh Town. The postcode is TR21 0NE.
For map apps, use 49.9187, -6.3054 or get directions in Google Maps.
How to Get There
There is no car park. English Heritage says the site is reached by an uphill footpath and is best visited on foot or by bike. Follow the road out of Hugh Town towards Porthloo, then look for the English Heritage sign and gate. The climb is short, but the ground is rough in places.
Opening Times and Entry
- Entry: Free
- Open: Any reasonable time during daylight hours
- Booking: Not needed
- Facilities: None on site. Use Hugh Town for toilets and food
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Do not expect a castle. What survives is a thick granite wall with a sharp, pointed bastion at each end. Historic England records the main wall at 27 metres long and up to 6.6 metres wide. The bastion walls reach 2.3 metres high in places. It is low, chunky and very solid.
The Two Bastions
The pointed bastions were the clever part. Their sharp angles let gunners fire along the face of the wall, so attackers had nowhere to hide at its foot. Historic England calls this the first fort in the country planned wholly around Italian style angled bastions. Had it been finished, it would have been well ahead of its time.
The Ditch and the Standing Stone
On the north west side, look for a wide ditch cut into the bedrock. It was meant to guard a wall that was never built. Just beyond it stands a granite standing stone about 2.75 metres tall, likely Bronze Age. Historic England suggests it survived partly because sailors used it as a marker for the harbour.
A modern navigation marker now stands right beside it, doing the same job.
The Harbour View
Pick a clear day. From the top you look straight down onto St Mary's Pool, with boats moving in and out below. Across the water sits The Garrison, home to Star Castle and the Garrison Walls. It is a good spot to watch the Scillonian or the tripper boats come into the quay.
The History of Harry's Walls
Why Is It Called Harry's Walls?
Harry was a common name for Henry, and over time people linked the fort to Henry VIII. The dates do not fit. Henry died in 1547. English Heritage confirms work started in 1551, under his son Edward VI. The name stuck anyway, and it is still used today.
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In the 1540s England feared attack from France and Spain. Henry VIII built a chain of coastal forts but did little on Scilly beyond sending 150 soldiers. Under Edward VI, money was found for a modern fort. Its job was to guard Hugh Town, where rising seas had opened up a large, sheltered harbour.
A letter dated 27 May 1551 told John Killigrew, who paid for the works, to build the fort on the little hill between the fresh water and St Mary's Pool. Historic England notes that timber was even framed in Wales, ready to ship. The plan showed a square fort with four bastions.
Why Was It Never Finished?
The hilltop was too small for the design, and the spot was a poor choice. Headlands blocked the guns from covering the main ways into the harbour. By 1554 the focus had moved to Tresco and King Charles's Castle. In the 1590s, Star Castle was built on The Garrison instead, says English Heritage.
So Harry's Walls is a Tudor mistake. That is exactly what makes it worth a visit.
Because work stopped part way, the site shows how these forts were built, something usually hidden in finished castles. Clearance work turned up an iron cannonball 8.25 cm across, sized for a small Tudor gun called a saker. Later on, the abandoned fort became a rubbish dump. It has been a scheduled monument since 1981.
Tips for Visiting Harry's Walls
- Wear good shoes. English Heritage warns of uneven ground and sheer drops.
- Stay off the walls. Climbing is not allowed on this protected monument.
- Keep children close near the edges of the walls and the ditch.
- Flying a drone? Check the English Heritage drone guidance first.
- Bring the story with you. English Heritage has a free audio tour online.
- Go late in the day for softer light over the harbour.
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Harry's Walls takes under an hour, so it pairs well with other sights. St Mary's has a lot of history packed into a small island. Here are the best add ons.
Porthloo
Carry on down the hill to Porthloo, a sheltered beach on the edge of St Mary's Pool. It makes an easy loop back towards Hugh Town.
The Garrison Walls and Star Castle
The fort that replaced Harry's Walls is across the harbour. Walk the Garrison Walls around the headland and see Star Castle, built in the 1590s. Seeing the two sites in one day shows why the builders changed their minds.
King Charles's Castle, Tresco
Harry's Walls has a sister fort on Tresco. King Charles's Castle was built in the same phase of works and became the islands' main stronghold for a time. It is a good reason for a boat trip.
Prehistoric Sites on St Mary's
English Heritage also looks after three much older sites on St Mary's:
- Bant's Carn Burial Chamber and Halangy Down Ancient Village
- Innisidgen Lower and Upper Burial Chambers
- Porth Hellick Down Burial Chamber
Isles of Scilly Museum
The old museum in Hugh Town has closed. A new Museum and Cultural Centre is due to open in spring 2027, so check before you plan around it.
Harry's Walls FAQs
Is Harry's Walls free to visit?
Yes. Entry is free and the site is open at any reasonable time in daylight.
Who built Harry's Walls?
It was begun in 1551 by the government of Edward VI, not Henry VIII. John Killigrew was paymaster for the works.
How long do you need at Harry's Walls?
Most people need 30 minutes to an hour, including the walk up from Hugh Town.
Is Harry's Walls suitable for wheelchairs or pushchairs?
It is tricky. Access is by an uphill footpath with uneven ground, so it is not easy for wheelchairs or pushchairs.
