The Duke of Buccleuch was a colourful and engaging figure among the dwindling band of non-royal dukes. He was a farmer, a forester, a politician and a man of notable energy.

After being paralysed and confined to a wheelchair, the result of a fall from his horse while out hunting with his father’s hounds in 1971, he simply started to get up at 5am instead of 7am because, he said, the same amount of work now took him longer and he liked to work at a comfortable pace.

With 280,0000 acres in the Scottish Borders and in Northamptonshire he was one of the UK’s biggest private landowners and one of the country’s richest individuals. He had three homes of great splendour – Bowhill and Drumlanrig Castle in Scotland and Boughton in Northampton, known as “the English Versailles” – and spent part of every year in each. (A fourth house, Dalkeith Palace near Edinburgh, where Queen Victoria used to invite herself to stay, preferring it to her own Holyroodhouse, is let to Wisconsin University as a European outpost.)

Buccleuch considered that his chief contribution to the family heritage was the restoration of the gardens at Boughton to their 18th-century splendour after 150 years of neglect: an elaborate system of canals was dug out, overgrown vistas were restored, miles of tree-lined avenues were opened up and statues were repaired – earlier generations had used them as cricket stumps.

In 1997, shortly before becoming Home Secretary, Jack Straw pointed to Buccleuch as a reason why Labour wished to abolish voting rights for hereditary peers in a reformed House of Lords. The Duke, explained Straw, with his background and his many acres, did not know “how the common man lived”. Within hours the Duke was holding forth on The World at One. He knew, he countered, exactly how ordinary people lived, revealing that during the Second World War he had served for four years as an ordinary seaman in a destroyer in the Atlantic.

Since then he had fought five elections for the House of Commons (he won four, lost his first but reduced a safe Labour seat to a marginal) and served in the Commons for 13 years. Furthermore, he employed 1,000 people on his estates and knew many of them personally. Straw, he concluded, was “just mesmerised by acres”.

The young Earl of Dalkeith – a courtesy title, he succeeded his father in the dukedom only in 1973 – was 15 when war was declared in 1939, and he joined up three years later, being listed as Ordinary Seaman J. Dalkeith. Looking back years later, he admitted that living through “a grey, angry Atlantic 28 days at a time” was responsible for his subsequent great love of the countryside.

In the House of Commons he served as PPS to the Lord Advocate, and later, before his accident, to the Secretary of State for Scotland. The Prime Minister to whom he probably felt closest was Alec Douglas Home, at whose memorial service in St Giles Cathedral, Edinburgh, he was to give a most moving address.

In 1971 he was the first postwar member of the Commons to enter the chamber in a wheelchair (Churchill in the 1959-64 Parliament used to be wheeled through the lobby but then hobbled to his seat).

When his father died in 1973, Johnnie Dalkeith succeeded him in the House of Lords, which he found less congenial than the Commons.

Although immobile, he never allowed himself to indulge in self-pity. Instead, he concentrated on practical self-help, making use of gadgets to grab marmalade jars off the table or to open field gates from the window of his car – which he had had modified so that its suspension could be raised for him to slide into it from his wheelchair. At Boughton, as at Bowhill and Drumlanrig, he was a familiar sight driving through the fields to inspect his livestock and crops.

Walter Francis John Montagu Douglas Scott, 9th Duke of Buccleuch and 11th Duke of Queensberry, was born in 1923. He was educated at Eton and Christ Church, Oxford, after which his father arranged for him to work in a small coal port near Edinburgh, owned by the family. From there he moved on to responsibilities on the Buccleuch Estates.

He was the first Duke of Buccleuch to open his homes to fee-paying visitors. He left the job to professionals, but his own personal touches were always in evidence (if he spotted a visitor he knew, he would always see to it that his or her entrance fee was returned on the way out on a silver tray). He also took a keen interest in the gift shops.

Buccleuch’s farming came to national notice during the BSE furore in the mid1990s. MPs worried about the provenance of the Palace of Westminster’s own beef supply were reassured when the chief Commons chef reported that 95 per cent of it was from the Buccleuch Estates.

In 1995 the Duke won the gold medal of the Royal Societies of England, Scotland, Wales and Northern Ireland for his contribution to the advance of agriculture. He had won the Bledisloe Gold medal three years earlier. In his time as chairman of Buccleuch Estates millions of trees were planted. Much of the planting was imaginative: trees were woven into farming landscapes in different colours and types to give the impression of a Paisley shawl. Spaces were left between plantings to reveal views of water and mountain, whenever this was possible, and to provide walks.

Rare books were another interest, and he was a member of that select group of bibliophiles, the Roxburgh Club. In 1978 he was appointed a Knight of the Thistle, of which order he was Chancellor, 1992-96.

In 1975 he was elected chairman of the Association of Lords Lieutenant. He was active in many charities in the fields of disablement, ambulances, agriculture and animal diseases, including the Central Council for the Disabled, the Royal Association for Disability and Rehabilitation, the Malcolm Sargent Cancer Fund for Children in Scotland and the Scottish National Institution for the War Blinded. People were very kind to those in wheelchairs, he used to say, but it worried him that they could often be impatient with the deaf.

The magnificence of the Buccleuch family’s collection of art – which includes works by Holbein and Rembrandt – came forcibly to public attention in 2003 when thieves posing as visitors strolled out of Drumlanrig Castle with Leonardo da Vinci’s Madonna with the Yarnwinder. Valued at more than £25 million, it has not been recovered, and the Duke received a reported £3 million insurance payout.

In the years after devolution, he took a keen and constructive interest in conservation and land reform. Although instinctively against some of the Scottish Executive’s new legislation, including the antihunting and land-reform Acts, he worked closely with organisations such as Scottish Natural Heritage to demonstrate that traditional land ownership had much to contribute in terms of allowing access to the public and demonstrating the best practices of conservation. At the same time, he oversaw the transformation of Buccleuch Estates from the ownership of rural land into a substantial commercial organisation, involved in urban property and development.

He is survived by his wife, Jane McNeill, whom he married in 1953, and by their three sons and daughter.

The Duke of Buccleuch and Queensberry, KT, VRD, MP Edinburgh North 1960-73, landowner and farmer, was born on September 28, 1923. He died on September 4, 2007, aged 83