The 10 strongest castles in Scotland

Stirling holds a volcanic crag ringed by cliffs on three sides, with only one gently rising approach to defend, the strategic clasp between Lowlands and Highlands, guarding the lowest bridging point of the Forth. Whoever held Stirling held the road north, which is why its walls, forework and later artillery batteries were kept formidable across four centuries.

It is one of Britain's most fought-over castles, changing hands again and again through the Wars of Independence. In 1304 Edward I ringed it with a dozen siege engines and built the largest trebuchet ever made, the 'Warwolf', then refused Sir William Oliphant's surrender until the giant engine had been fired at the walls. The thirty-man garrison finally gave in on 24 July 1304. Mighty, but taken more than once precisely because it was the prize.

Edinburgh sits on a sheer volcanic plug, Castle Rock, with cliffs falling away on three sides and only the ridge down the Royal Mile to climb, that approach barred by the gatehouse, portcullis gate and the great curved Half-Moon Battery. It dominates the capital it was built to hold.

It is the most besieged place in Britain, with some twenty-six recorded sieges, and it was breached more than once. In 1314 Thomas Randolph's men scaled the north cliff by night and stormed it back from the English. During the Lang Siege of 1571-73 the Marian garrison under Kirkcaldy of Grange held for nearly two years until English heavy guns under Drury battered David's Tower into collapse; they surrendered on 28 May 1573.

Dumbarton stands on a twin-peaked volcanic rock rising some 240 feet sheer from the Clyde, the longest-recorded stronghold in Britain, capital of the British kingdom of Strathclyde long before it was ever a royal castle. The rock itself does most of the defending; there was never much need for elaborate walls.

Yet even the strongest natural fortress fell to nerve rather than force. Before dawn on 1 April 1571, Captain Thomas Crawford of Jordanhill led about a hundred men up the steep north-east face with scaling ladders, guided by a former warden of the garrison, and surprised the Marian defenders in their beds. Taken by escalade, not by battering.

Tantallon seals off a headland with one of the mightiest curtain walls in Scotland, some fifty feet high and up to twelve feet thick, while sheer sea cliffs guard the other three sides. The single landward approach was covered by a wide ditch and earthworks, later stiffened with a gun tower and a ravelin for the age of artillery.

The Red Douglas stronghold was besieged by James IV in 1491 and by James V in 1528, whose gunners pounded it for twenty days ('Ding doon Tantallon!') without breaching the wall, it passed to the crown by terms, not assault. It fell only in 1651, when General Monck's Cromwellian siege train hammered it for twelve days and tore out the end towers, ending it as a fortress.

Britain's only triangular castle, Caerlaverock is a masterpiece of design rather than of position: a twin-towered gatehouse, high curtain and a double water-moat drawn from the surrounding Solway marsh do the work a crag does elsewhere, because the ground is flat. Its record is mixed. In July 1300 Edward I's army, set down in wonderful detail by the heraldic Roll of Caerlaverock, forced its sixty-man garrison to yield in two days; it was taken and slighted more than once after. Its last fight came in 1640, when the Maxwells held for Charles I through a thirteen-week siege before surrendering to the Covenanters, who then dismantled it.

The largest and most ambitious stone castle of thirteenth-century Scotland, Bothwell was built around a huge circular donjon without parallel in the country, cut off by its own moat on a bank above the Clyde. But its ambition outran its luck. In August 1301 Edward I took it after about three weeks, wheeling up a giant timber siege-tower, the 'belfry', to storm the great keep. When the Scots recovered it they deliberately wrecked it: Sir Andrew Murray pulled down the whole west side of the donjon so the English could never hold it again. Magnificent, never completed, and repeatedly taken.

The 'ship that never sailed' juts into the Firth of Forth on a rocky spit, water on three sides. Between 1537 and 1543 Sir James Hamilton of Finnart rebuilt it as one of Scotland's most advanced artillery forts, immensely thick walls raised to carry heavy guns, a caponier covering the entrance passage, gunholes and murder-holes, and it stayed a working garrison and arsenal for centuries afterwards. It fell once: in 1650 Cromwell's forces bombarded it from land and sea until the garrison surrendered, artillery having finally outgrown even Finnart's walls.

Set on a promontory into Loch Ness, Urquhart guarded the Great Glen behind a gatehouse and the tall Grant Tower. The position was strong; the record was not. It changed hands throughout the Wars of Independence and was raided again and again by the MacDonald Lords of the Isles, who seized it outright in 1452 and stripped it bare in the 'Great Raid' of 1545. Held at the last by a government garrison, it was partly blown up by its own defenders in 1692 to keep it from the Jacobites, a fought-over strongpoint more than an unbreakable one.

'The strength of Liddesdale', a grim, near-windowless block guarding the Scottish Middle March, its corner towers joined by dramatic flying arches and its walls ringed by a moat and screened further by the Hermitage Water and marshy ground. It was built for war and nothing else. Its very construction in the thirteenth century brought Scotland and England to the brink of war; it was captured by the English in David II's reign and retaken by Sir William Douglas. Its life was one of endless border violence rather than a single great siege, a fortress that ruled its valley by menace as much as by walls.

A cluster of thirteenth-century round towers on a rocky outcrop, later eased into a comfortable residence with walled gardens, the most house-like castle on this list, and ranked here for it. It was stormed twice. In 1298 Bishop Antony Bek of Durham, campaigning for Edward I, took it and let the garrison walk free; in November 1650 Cromwell's Generals Monck and Lambert smashed its drawbridge and gate with mortars, captured it, and slighted it for good. Strong enough in its day, but never a first-rank stronghold.