Lindisfarne Castle sits on a crag on Holy Island, reached only across the tidal causeway from the Northumberland coast. Built in the 1540s as a fort using stone from the ruined priory, it was bought in 1901 by Edward Hudson, who had Edwin Lutyens turn it into an Arts and Crafts holiday home; the National Trust has cared for it since 1944. Inside, the bedrooms have been dressed with period pieces, and volunteers on the upper battery set up a scope for spotting grey seals on the sandbanks. Across the field is the small walled garden designed by Gertrude Jekyll, free to visit, as are the lime kilns and shoreline walks. Reviewers praise the welcoming staff and the clear storytelling. Tips from visitors: check the safe crossing times, as the road floods twice a day; it is a mile each way from the village pay and display car park; expect a steep cobbled ramp and steps; and arrive early, as the island fills up even midweek.