My brother Ian Buist, who has died aged 82, was a colonial officer, overseas administrator and champion of human rights. He was a scion of a highly intellectual Scottish family whose legacies formed his core beliefs. A major scholarship to Winchester college and a double first in classics at New College, Oxford, were followed by top place in the civil service exams. He joined the colonial service because, he said, "people should be judged on how they execute their responsibilities to others".
He handled the East Africa desk throughout the Mau Mau crisis in Kenya in the 1950s, and during the Queen's coronation in 1953 escorted several Ugandan kings around London. He later moved to the Foreign and Commonwealth Office where he pursued, regardless of the consequences, the dictates of his conscience and his formidable intellect.
He was determined to abolish race-based appointments in the Kenya police; this was achieved without too much rancour. His work in ending white privileges over land ownership won widespread respect and helped Kenya towards independence in 1963. He worked tirelessly to help the most invisible and disadvantaged, a passion he pursued until his death.
Ian was masterful at international negotiations and his familiarity with the nuances of English was politically invaluable. With sequential postings to several international banks, he administered a budget designed to lift millions out of poverty.
Ian was the first senior civil servant to declare his homosexuality openly. He was almost discharged from the service but, with strong support from above, was eventually cleared of possessing a "serious character defect", the prevailing view of the civil service code with regard to homosexuality. For decades he was an active member of the Lesbian and Gay Christian Movement and central to its battles for full equality, writing outstanding submissions to the church, parliament and others.
He was a consistent churchgoer although he professed to a firm "faith without belief". Music was a passion: he was an organist for Trinity United Reformed church in Wimbledon, south-west London, and a long-time member of the Thames Philharmonic and Wimbledon Academy choirs.
For more than 20 years, Ian was a board member of Plan International UK– a perfect outlet for his skills in overseas development and international aid. He persuaded it to adopt a new focus on girls and women at risk.
He lived modestly but his generosity cascaded around the world to friends in need. He will be remembered for his phenomenal memory and analytical skills, and as a kindly, gracious, humble and amusing man.
Our brother and sister predeceased him.