Alnwick Castle

Where it sits. Alnwick Castle occupies a low bluff on the south bank of the River Aln, at the northern edge of the Northumberland market town of the same name, roughly 55 kilometres north of Newcastle upon Tyne and about eight kilometres inland from the North Sea at Alnmouth. The coastal plain rolls east towards the dunes; the Cheviot Hills close the western horizon. The walled enceinte encloses some three hectares, which makes this the largest inhabited castle in England after Windsor. It has been the seat of the Percy family — Dukes of Northumberland since 1766 — for more than seven centuries, and the family still occupies the southern range, so individual rooms can close at short notice.

The story behind it. A Norman motte-and-bailey went up here around 1096 under Yves de Vescy, guarding the crossing of the Aln on the road to Scotland. Henry de Percy bought the barony in 1309 and set about turning timber and earth into stone: the shell keep with its ring of semicircular towers, the barbican, and the gatehouse that still forms the visitor entrance. Three centuries of border warfare followed, and by the eighteenth century the fabric was half-ruined. The first Duke commissioned Daniel Garrett and Robert Adam to fit out Gothick interiors in the 1750s while Lancelot "Capability" Brown reshaped the park below. That work was itself swept away when the fourth Duke, Algernon, hired Anthony Salvin to rebuild the exterior between 1854 and 1865 and brought in the Italian designers Luigi Canina and Giovanni Montiroli for the Renaissance interiors visible today. The stone sentries standing along the battlements are decorative eighteenth-century carvings, not medieval work.

On screen. Filming for Harry Potter and the Philosopher's Stone took place here in the autumn of 2000, and the castle supplied the film's most-quoted piece of Hogwarts grounds. The grassy Outer Bailey — the wide lower court inside the curtain wall — is where Madam Hooch drills the first-years in broomstick flying, where Neville's broom bolts skyward, and where Harry dives to catch the Remembrall. The same court doubles as the practice pitch for Oliver Wood's Quidditch tutorial. Two years later the production returned for Harry Potter and the Chamber of Secrets and used the Inner Bailey, the tighter cobbled court beside the keep, for the aftermath of the flying Ford Anglia's crash landing. It is worth being precise about what Alnwick did and did not provide: no interiors were shot here. The Great Hall, the moving staircases, the common rooms and the corridors were all built at Leavesden, and the sweeping castle silhouette in the wide shots is a 1:24 scale miniature, not Alnwick's roofline. What the castle gave the films was scale, weathered stone and real Northumbrian weather. Other productions have used it heavily too — Elizabeth (1998), Robin Hood: Prince of Thieves (1991), Downton Abbey's Brancaster Castle, and Transformers: The Last Knight.

What you actually see today. The visitor route runs through the barbican into the Outer Bailey, then across to the keep and the State Rooms. The Library, lined in Austrian oak with something in the order of 16,000 volumes, is the room most people remember; the Saloon and Dining Room carry Canina's coffered ceilings and a picture collection that includes Titian, Van Dyck and Canaletto. The Abbot's Tower holds the museum of the Northumberland Fusiliers, and the Postern Tower displays archaeology from the estate, including Roman material from nearby sites. In the Outer Bailey, staff run short broomstick training sessions through the day — genuinely aimed at children, and the queue is longest just after opening. Knight's Quest, Dragon Quest and the Lost Cellars trail fill the rest of a family visit.

Next door. The Alnwick Garden, begun in 1997 as the Duchess Jane Percy's project and laid out by the Belgian designers Jacques and Peter Wirtz, sits immediately west of the castle behind its own walls. The Grand Cascade steps water down 21 weirs, the Poison Garden is opened only on guided tours, and the treehouse restaurant is among the largest wooden structures of its kind in the world. It charges separately, though joint tickets exist.

Getting there and timing. Alnmouth station, on the East Coast Main Line, is eight kilometres away with frequent taxis and the X18 bus; London to Alnmouth takes a little over three and a half hours. Drivers come off the A1 at the Alnwick junction and park at Greenwell Road, a five-minute walk from the barbican. The castle interiors generally open from late March to the end of October; the grounds and the town stay lively year-round. Northumberland weather is unsentimental, so bring a layer even in July, and expect the Outer Bailey to be at its emptiest in the last two hours before closing.