Although he inherited a string of titles, several great houses and many thousands of acres, David Wemyss was clear where his interests lay. He devoted himself to those matters where he believed he could make a difference — to Scotland, its heritage and environment, and to public service. His 47-year association with the National Trust for Scotland, as member, chairman of council, president and president emeritus, changed the whole course of that organisation.

Not only did it, during its critical postwar period, acquire and conserve some of the most important historic buildings in Scotland which might otherwise have been lost, it changed perceptions about the country’s natural heritage. It was instrumental in protecting the sites of battlefields, such as Culloden, which were under threat from development, areas of great natural beauty, such as the Torridon Hills, and Hebridean islands, whose fragile ecology the trust helped to preserve.

All of this was achieved under his auspices — his partnership with the trust’s director, Jamie StormonthDarling, being a particularly fruitful time. His was a practical approach. He liked nothing better than scrambling up the scaffolding of an ancient building to inspect a crumbling battlement, and even to effect running repairs — at Neidpath Castle, a 14th-century keep overlooking the Tweed, which his family owned, he fixed the pointing himself, at considerable risk to life and limb. He liked the company of those directly involved in conservation, whether stonemasons or gardeners, and up until a few weeks before his death at the age of 96, he was still setting off, resolutely, from the family house at Gosford in East Lothian, driving a golf buggy to inspect the work of the foresters on the estate. The fact that he occasionally collided with cars in the car park, and was once found upside down in a ditch having turned the machine over, did nothing to put him off.

His sense of duty was apparent in a host of other activities which involved him in many aspects of public life in Scotland, including his charitable work with the Marie Curie Foundation, his chairmanship of the Royal Commission on Ancient Monuments, and the unprecedented three stints he fufilled as Lord High Commissioner to the General Assembly of the Church of Scotland.

Francis David Charteris, 12th Earl of Wemyss and 8th Earl of March, was born in Stanway, Gloucestershire, in 1912 during the so-called “Edwardian summer” and his life thus spanned a wide period of much social change in Britain. His father, Captain Lord Elcho, was killed in action in Egypt in 1916 at the age of 31, leaving David and his brother Martin Charteris, later private secretary to the Queen, fatherless at the ages of fourand three. Their mother was Lady Violet Manners, daughter of the 8th Duke of Rutland. He inherited the title on the death of his grandfather in 1937.

Educated at Eton and Balliol College Oxford (he graduated BA in 1933), he also studied agriculture as a postgraduate student at both Oxford and Cambridge. He was commissioned into the territorial Lovat Scouts, and in 1937 was appointed an assistant district commissioner in Basutoland (now Lesotho).

He always looked back at his period in Africa as one of the happiest of his life because he was free of the heavy burden of his land and titles, which meant little to the people of Basuto, and with whom he forged a close affinity.

On the outbreak of war he was prevented from rejoining the Lovat Scouts, and instead served as a major with Basuto troops in North Africa, because he was one of the few officers who could speak to them in their own language. Later, with the Eighth Army, he was employed as a staff officer at GHQ Middle East.

It was while he was in Basutoland, that he met his wife Mavis, daughter of Edwin Murray, of Hermanus, Cape Province; known universally as Babs, she was working in the secretariat of the High Commission. On their return to Britain, they lived at Gosford, a vast 18th-century house built to plans by Robert Adam and famed for its marble hall and stunning collection of old masters. It had had been occupied by the Army during the war, and was

in desperate need of restoration. Wemyss had been approached by the chairman of the National Trust for Scotland, Sir Iain Colquhoun of Luss, to be vice-chairman, and when Colquhoun fell ill in 1946, Wemyss succeeded him.

In the postwar period many stately homes in Scotland came under threat, and several were demolished by their owners who viewed the Labour Government’s death duties as a threat to their future existence. The trust found itself standing as a bulwark against those who argued that these monuments to the past had no place in the modern Scotland.

Gradually it extended its portfolio, acquiring such iconic buildings as Craigievar, Brodick and Crathes Castles, Falkland Palace, part of Charlotte Square, gardens like Pitmedden and Inverewe, and, at least as important, the islands of St Kilda, Fair Isle and mountainous regions such as Ben Lawers and the Torridon Hills.