Sinclair Horne was born in Port Seton, East Lothian, on 9 March 1927. At the age of 14, he pursued his childhood dream of going to sea. He became a cabin boy on a boat acquired by the Army to move troops and supplies around Scotland.
The trip ended in Oban, and after the first weekend there he contacted a family friend living in the town. The friend invited him to Oban Baptist Church to attend special services being held for the troops. He went along, and on Monday, 3 November 1941, he became a Christian. This was the turning point in his life.
In 1946 he was called up for National Service and was involved with the Army Scripture Readers and chaplaincy work. He considered continuing with this, but felt he was being led in a different direction.
On his return home, he began studying part-time at New College, Edinburgh, while working as a fishmonger in Loanhead, south of Edinburgh.
As part of his studies, he was an assistant preacher in the Reformed Presbyterian Church in that village. He was ordained as a minister of the congregation in 1955.In 1964 he resigned as minister of Loanhead to become secretary of the Scottish Reformation Society.
He was a tireless worker, and in addition to his extensive duties as secretary, he was also lecturer for the Society, visiting many parts of Scotland and northern England to speak on aspects of Protestantism and the Reformation.
He also produced films, gave tours in Edinburgh, St Andrews, and various covenanting sites, as well as on the continent.
In 1968 he published Torchbearers of Truth, and in 1974 (with J. B. Hardie) his highly useful In the Steps of the Covenanters.
From 1981 to 2008 he was editor of The Bulwark. In 1972 he organised a meeting addressed by Dr Martyn Lloyd-Jones for the 400th anniversary of John Knox’s death, attended by nearly a thousand people.
The historic Magdalen Chapel became the headquarters of the Society. Sinclair very much enjoyed welcoming visitors to the Chapel and leading tour groups around Edinburgh. His welcome often left a deep impression on visitors.
In 2008 he resigned as secretary of the Society, but continued to act as curator of the Magdalen Chapel until 2016. He died, ready for glory, on 27 April 2021, aged 94.