THE Dunmore Pineapple bears the date 1761. It is a folly, architect unknown. There is no other building like it in Scotland, and no obvious link to any aspect of the life of John Murray, 4th Earl of Dunmore, who had it put up on his estate. It stands in its singular splendour close to Airth in Stirlingshire.

For the opening of new horizons in different parts of Scotland, and the advertising of novelty, change and growth, 1761 was a good year.

After two German Georges had worn the crown in London, there was now an English-speaking king, George III, who promised to “glory in the name of Britain”.

He intended to rule as well as reign. This was the principle of kingship he had learned at the feet of his personal tutor, John Stuart, 3rd Earl of Bute, who was soon made prime minister.

Stuart was a man of high ideals, but a Scottish nobleman too. He did not, like others of his rank, spend as much time as possible in London, seeking favour for himself. He liked to be at home on the island he shared his name with, devoting his time to reading, agriculture and his lifelong passion, the study of botany.

He also sought contact with talented young Scotsmen who might be useful for public purposes as a new reign began. One was the Earl of Dunmore, already notable for his strange, sinuous pineapple tree. For all we know, it could have been gifted by Stuart.

The National: Left to Right: John Stuart, 3rd Earl of Bute and John Murray, 4th Earl of DunmoreLeft to Right: John Stuart, 3rd Earl of Bute and John Murray, 4th Earl of Dunmore (Image: Google)

Stuart lived in a big house, Mount Stuart, on the island of Bute. Extensive grounds were thought necessary for a nobleman of the north, to show how land and crops could be protected from wind and frost behind a high wall of stone or brick.

More and more of his peers had done some imperial service, and now they could show off ornamental plants at an alien latitude, with a variety of exotic fruits and vegetables in sheltered spots on their estates.

It was a metaphor of social standing but it also had a scientific purpose in creating different experimental microclimates.

In 1761, pineapples were still among Scotland’s most exotic foods. Those grown by Dunmore showed he was a man to reckon with.

His horizons widened as he added foreign dimensions to his career. In the autumn of 1771, he was posted to Williamsburg, the sleepy capital of colonial Virginia. He was by now a professional soldier – the sort of man the Crown liked to appoint to delicate, distant positions.

Often, blue-blooded governors were regarded as so inherently reliable that they did not really need to turn up at the places where they were supposed to be in charge. It would be different from now on because in America the relations of rulers and ruled came under strain.

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Lord North’s government in London was in office from 1770. For much of its time it was at war with other European powers, and successfully so.

The emergence of a global Empire was not cost-free, however. Huge taxes had to be raised to pay for it all. North thought they should be raised from Americans, too, because they were British subjects benefitting from imperial protection.

In London it was finally decided the Americans should be compelled to pay their share if nothing else worked. The result of this policy was to provoke the War of Independence, waged from 1776-83. It finally showed that the British could not control America.

The government in London entertained its highest hopes of the southern colonies, where more recent white immigration was thought to set a better example of loyalty.

General Charles Cornwallis led an army in 1780 on a march from Charleston, South Carolina, through the backwoods towards Charlotte, Virginia, in the hope of recruiting soldiers as he advanced.

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Eventually, he turned aside to Chesapeake Bay and set about building a fortification at Yorktown which might dominate Virginia, a territory of rich rebels.

But the French had now entered the war on the American side and sent a fleet to cut Yorktown off from the sea. Meanwhile local forces laid siege from the land. Cornwallis had no choice but to surrender. It was the end of active campaigning by royal forces in this war.

Dunmore had meanwhile assembled a different array of martial might.

He was appointed governor of New York in 1770 and of Virginia in 1771.

In those days, few in the British ruling class took it amiss if governors drew private profits from the colonies. It was reckoned to give them an interest in the job.

Dunmore did well out of speculations in partnership with a big landowner in Virginia, by the name of George Washington.

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Wives and daughters in the transatlantic society felt delighted that Lady Dunmore and their eight children crossed the ocean too, arriving in 1774. Hardly were they there than the earl set off on a military expedition to the western end of Virginia defending the line of the Appalachian Mountains against Native American marauders.

It diverted Dunmore from imperial affairs, and the acclaim for his victories may have blinded him to the strength of an opposition building up in Virginia and elsewhere.

In Boston they held the Tea Party to protest against customs charges on imports. In response, MPs at Westminster passed punitive laws. At Williamsburg legislators took the side of Massachusetts. In May 1774, Dunmore dissolved his assembly.

Amid these upheavals, Williamsburg remained a kind of executive village. Mrs Martha Washington, normally resident at Mount Vernon on the Potomac River, had her own house in the colony’s capital for use during legislative sessions.

William and Mary College was the centre of its intellectual life. From a place not easily defended, Dunmore decided in April 1775 to shift his governor’s office.

He shipped everything down to the port of Norfolk at the entrance to Chesapeake Bay. It had a loyalist population living off global trade, including Scots who sent Virginia tobacco to Glasgow and further.

For security, Dunmore installed himself on a man-of-war in the harbour. He explained to colleagues: “I have thought it best for his Majesty’s Services to retire from amidst such hostile appearances around me.”

Dunmore tried a second ploy, described in correspondence between two Virginian lovers of liberty (and slave owners), Richard Henry Lee and Thomas Jefferson. Lee derided Dunmore as the “African Hero” because he offered freedom to any slave deserting his master to become a soldier to George III.

In this and in coming wars, the enslaved population proved a useful source of military recruitment. Now “liberation fever” spread over the disloyal districts. Black mothers named their newborn babies Dunmore.

In November 1775, Dunmore made it official that there would be freedom for slaves and indentured servants “appertaining to Rebels” if they enlisted under the royal banner. But the next month he was unable to hold off a Virginian force attacking Norfolk on the landward side.

He lingered offshore till May 1776. The Virginians again drove him away in July, and in August he finally abandoned Chesapeake Bay.

Dunmore crossed the ocean again to resume his former status as a Scottish representative peer. At Westminster he led the lobbying for compensation to American loyalists.

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He advocated a second front, with royal forces to land round the Gulf of Mexico and up the Mississippi River. It was too late for anything so ambitious, but Dunmore did cross the ocean yet again, now in the opposite direction because, tempted by the command in Charleston, he thought he could extend his plans for the recruitment of black people – 10,000 of them – under loyal officers.

The plan would be to reconquer the southern colonies but Dunmore failed to persuade fellow generals of his idea’s merits and nothing came of it.

With the War of Independence lost, in 1786 Dunmore went on to serve as Governor of the Bahamas. Many loyalists took refuge there, bringing slaves with them.

As the 13 colonies languished under blockade, trade was sought with Spanish Florida. Dunmore strengthened the islands’ defences and opened freeports for commerce in the Caribbean. But the Royal Navy now controlled barely half the Atlantic. It was a costly business that often disappointed commercial expectations.

Decades of world war would pass before British maritime supremacy again opened up the freedom of the seas, and then by victory in battle.