Robin entered the world in a well-to-do upper-class household, with a retinue of servants in their London home and on their Highland estate. But the Sinclairs were not active in London "society", always preferring their ancestral home in the rural community of north-east Caithness. As a boy, the young Robin Sinclair grew attached to the country way of life. He was later to become the proud owner of one of the fine salmon rivers of Scotland - the Thurso - and spoke knowledgeably on the subject, both in his time in the House of Lords and at learned conferences. During a spell when he somewhat eccentrically lived on a houseboat near Richmond during the Lords' sittings, he reintroduced salmon to the Thames. Deerstalking and shooting were also among his boyhood pursuits.
Jo Grimond used to recall the Highland Games organised by Sir Archibald Sinclair as well as the rich panoply of the political house guests with whom the young Robin discussed politics, among them Churchill himself, Harold Macmillan, Robert Boothby and Lady Violet Bonham Carter. Sir Archibald's biographer writes of how, on the day of the Munich "settlement" (which he strongly opposed), the Sinclair sons, Robin and Angus, were sent home from Eton because there were not enough gas-masks to go round. They expected to board the night train to Scotland; instead, they were told to go directly to the House of Commons. Here, they found their father talking to Churchill in deep mutual disapproval of Chamberlain. Churchill scowled at them: "It looks as though you'll have to go back to studying Greek."
In 1941, Robin Sinclair enlisted in the RAF, and spent his war service flying Mosquitoes in the Far East. On his demobilisation, he faced the disaster of his father, as leader of the Liberal Party, narrowly losing his Caithness and Sutherland seat in the 1945 election. Later elevated to the House of Lords, he suffered a debilitating stroke in 1959 which meant that Robin had to take over increasing responsibility for the family estate.
Yet he was not content just to do that. In the 1966 general election, he contested the unlikely seat of East Aberdeenshire for the Liberals. As a newly elected MP, I recall campaigning with him in the run-up to the election. His personal magnetism was considerable. He had inherited both his father's renowned good looks and his habit of wearing the kilt when north of the Border. He strode around the towns and villages of Aberdeenshire cutting a fine and eloquent dash, and ending with a creditable second place out of four in a not particularly vintage year for the Liberals.
In 1970 he inherited the viscountcy, and took a reasonably active part in the House of Lords, as though to make up for his father's long incapacity. These were the houseboat years. Later, when he became Lord- Lieutenant of Caithness, his attendances were less frequent and his speeches confined to more local matters, among them his strong advocacy on behalf of Dounreay. Indeed, I recall his taking me round the installation as party leader, and explaining the technology with a lucidity which escaped the nuclear boffins.
He was also founder chairman of the now hugely successful Caithness Glass company, raising £50,000 to start risky new employment, and for many years he was an active President of the Boys Brigade movement world-wide. His last speech in the House of Lords, on 8 February, was on the subject of the savaging of the rail services in Scotland. "It is no good making a better mousetrap," he said, "if the world cannot find a path to your door to buy it, or if you cannot find a satisfactory and economic means of delivering it to would-be buyers."
He and his wife Margaret were an immensely popular couple, devoted to the people and interests of mainland Britain's northernmost county. The disappearance of his tall, charismatic figure as a member of the Royal Company of Archers at Holyrood Palace, or kilted in the Highlands, will leave a gap in the landscape as well as in the life of Scotland.
The last 18 months have seen a swathe cut through a close-knit generation of Liberal stalwarts: Jo and Laura Grimond, Mark Bonham-Carter (Laura's brother), Elizabeth Lyle and now the latter's younger brother, Robin Thurso. They would all have been proud to see Elizabeth's daughter, and Robin's niece, Veronica Linklater, continue the family tradition as Liberal Democrat candidate in the Perth and Kinross by-election.
Robin Macdonald Sinclair, landowner, politician and businessman: born London 24 December 1922; County Councillor, Caithness 1949-61, 1965-73; President, North Country Cheviot Sheep Society 1951-54; Town Councillor, Thurso 1957-61, 1965-73, Baillie 1960, 1969; Chairman, Caithness and Sutherland Youth Employment Committee 1957-75; founder in 1964, and first chairman, Caithness Glass Ltd 1964-66; Vice- Lieutenant of Caithness 1964-73, Lord-Lieutenant 1973-95; member, Red Deer Commission 1965-74; succeeded 1970 as second Viscount Thurso; President, Highland Society of London 1980-82; Brigade President, Boys Brigade 1985-93; married 1952 Margaret Brokensha (ne Robertson; two sons, one daughter); died Thurso 29 April 1995.