Sir William Garth Morrison

Garth Morrison, who has died aged 70, was a Royal Navy officer and a farmer but was best known for his long involvement with the Scouts. He rose to become head of the Scout Association, known as Chief Scout for the UK and Overseas Territories, from 1988 to 1996.

He was born in Edinburgh in 1943 and attended Pangbourne College boarding school in Berkshire, where he became head boy and captained the English Schools under-15s rugby union team.

He moved to the Britannia Royal Naval College in Dartmouth, Devon and later Cambridge University, where he graduated Bachelor of Arts in 1966, having been three years a "Blue" for his athletic prowess and captain of the university golf club. He served as an engineering officer in the navy for 12 years, most of this time serving in nuclear submarines, retiring with the rank of lieutenant in 1973.

Thereafter, he split his time between his Scout work and running his 560-acre farm in West Fenton, near Gullane. He provided grains for Scottish breweries and distilleries, horse livery, cottages for golfing and other tourists, and there was a much-praised riding school on his land – Muirfield Riding Therapy, part of the Riding for the Disabled Association – which helps rehabilitate disabled people.

After retiring from the navy, Sir Garth held numerous positions in the Scout Association, starting in 1973. These included area commissioner for East Lothian and chief commissioner for Scotland. He received scouting's Silver Wolf Award in 1982.

The following year, he attended the 15th World Scout Jamboree in Alberta, Canada, and, in 1987, the World Jamboree near Sydney, Australia. He was appointed Chief Scout for the UK and Overseas Territories (former colonies or dependent territories) in 1988, retaining close links with the Scouts after his term as chief ended in 1996.

The Chief Scout is a post first held by the founder of the movement, Robert Baden-Powell (in those days the title was Chief Scout of the British Empire) and currently by the adventurer and television presenter Bear Grylls.

Sir Garth, who remained vice-president and president of the Scottish Scout Association, was credited with many of the changes that underpinned the growth of scouting in Scotland, the UK and worldwide. He tackled stereotypes to make the movement more appealing to a range of backgrounds, partly by spearheading a more relaxed atmosphere and more enjoyment, and partly by easing the uniform rules to make young people feel more relaxed about wearing it. He was also instrumental in the inclusion of girls in scouting.

During his tenure as Chief Scout, Sir Garth was heavily involved in the Promise Appeal, which culminated in 1992 with fundraising activities by Scout groups across the UK, including seeking grants from the corporate sector. The appeal raised £2.5 million.

Sir Garth served as Deputy Lieutenant for East Lothian from 1984 to 2001 before being appointed Lord Lieutenant for East Lothian in 2001, an honorary post he held until his death. He was a member of the Society of High Constables and the Guard of Honour at the Palace of Holyroodhouse, as well as a board member or trustee of numerous organisations, including the Lothian and Borders Committee of the Royal Jubilee and Prince's Trust, the Royal Infirmary of Edinburgh and the National Lottery Charities. Wearing his farmer's hat, he was a past president (2009-10) of the Royal Highland and Agricultural Society of Scotland.

He was made CBE in 1994 for his work in the voluntary sector and created Knight of the Most Ancient and Most Noble Order of the Thistle by the Queen in 2007, giving him the title Sir. Despite the title, he was rarely happier than when developing the scouting movement or running the family farm.

While paying the bills by growing the grains that became beer or whisky, Sir Garth and his wife Gill were deeply involved in more modern forms of farming. Parts of their land were given over to holiday cottages, renovated from Victorian stables and attracting tourists from the UK and beyond. Golfers who came to play Gullane, North Berwick, or even Muirfield often rented the self-catering cottages for their tranquillity.

All of that helped pay the bills, but Sir Garth and Gill gave back to the community around their farm and throughout East Lothian. With Sir Garth a financial and moral stalwart, and Gill hands-on (and reins-on), they developed what they called Muirfield Riding Therapy, a riding school on their farm that used the natural empathy between ponies and young – or even older – people with mental or physical disabilities. The school has changed many people's lives, something that gave the couple massive pride.

Two of his proudest moments were being appointed to the Order of the Thistle by the Queen in 2007 and, as a Lord Lieutenant, being invited to the wedding of Prince William and Kate Middleton in Westminster Abbey in 2011. "On the one hand, it was a magnificent occasion being witnessed by well over a billion people around the world," he said after the wedding. (Statistics later suggested it was more like two billion.) "But it was also a terribly important moment in the lives of two young people."

Afterwards, American TV presenters, most of whom had not been allowed into the abbey, sought out Sir Garth for his comments on what it had been like inside. Why him? "I was wearing my kilt, which probably marked me out a little bit," he later said. "My son was in Mexico at the time and he told me later he'd seen me on YouTube."

Following his death the Queen sent a letter of tribute to Sir Garth's wife, Lady Gill Morrison. Sir Garth had been diagnosed in November with cancer of the oesophagus, for which he received successful treatment and an operation. However, the disease returned.

Lady Gill said: "He had a very strong faith and we both discussed the fact we come into this world and we go out of it, and we've had 43 very happy years together. He was very loved and I think it's because he had such an even temperament.

"You talk about people having an edge, but he had no edge at all. He was just a very warm person. He quietly got on with what he was doing but appreciative of what other people were doing."

Sir Garth was involved in several royal visits to Scotland and carried out duties such as delivering telegrams from the Queen to those celebrating 100th birthdays. He enjoyed golf, sailing, rugby and his continuing links with the Scout movement. He died at home in West Fenton and is survived by his wife, sons Alastair and Chris, daughter Clare and six grandchildren.