John Johnstone of Alva (1734-1795) was the son of Sir James Johnstone, 3rd Baronet, and Barbara, daughter of Alexander Murray, 4th Lord Elibank. Johnstone was educated in Edinburgh before taking the role as a writer in the service of the East India Company in 1750. Between 1751 and 1765, Johnstone took on a series of important roles within the Company, becoming a member of the Bengal Council and serving in the artillery. He was imprisoned for a short period in 1756 due to hostilities between the Nawab of Bengal, Siraj ud-Daula, and the Company.

His various appointments gave him the opportunity to trade privately, particularly in salt. He then formed a partnership with two other Company servants, William Hay and William Bolts and became involved in revenue farming. From this, he was accused of malpractice and fraud, having come into conflict with Henry Vansittart, the Governor of Bengal, and was dismissed in 1764. Within months he was reinstated and returned to Bengal and continued his business, receiving approximately £36,000 worth of gifts, the largest amount given to any individual involved at the time. In 1765, Robert Clive became Governor of Bengal and brought with him a reform which further called into question Johnstone’s conduct, resulting in Johnstone’s resignation.

He returned to Scotland with a large fortune and purchased estates at Alva in Stirlingshire, and in Selkirkshire and Dumfriesshire. He faced prosecution by the East India Company for his activities in Bengal and published A Letter to the Proprietors of East India Stock in 1766 in his defence. He and his brothers succeeded in obtaining the withdrawal of prosecution in 1767 and his brothers, George and William, formed part of the Parliamentary Select Committee of inquiry into the company in 1772. Johnstone was elected MP for Dysart Burghs in 1774 and supported the opposition to the North administration. He lost his seat in 1780 and made an unsuccessful attempt for a seat in Dumfriesshire. He died at his home, Alva House in 1795.

Johnstone acquired the Denovan estate in 1773. Roy’s Military Survey of Scotland shows a property on the site from the mid-eighteenth century. The surviving Adam office designs are for a house with offices and it is unclear if these incorporated the existing property or were a complete replacement. The surviving drawings are undated and there is no known information to indicate a date other than Robert Adam’s additional work for Johnstone at his estate in Alva, and a family mausoleum in Westerkirk which all date from 1789-91. The Adam office had previously made designs for Johnstone's uncle, the 5th Lord Elibank, for a monument to his wife in 1762-63, and also for Johnstone's brother, Sir William Pulteney (formerly Johnstone), a friend of Robert Adam's, for works in Shrewsbury and Bath.

It is also not clear if the designs for Denovan House were executed. The estate was bought by William Forbes of Callendar in 1839, followed by James Graham Adam in 1843, and subsequently extended and remodelled entirely in the Jacobean style. The listing description makes reference to the existence of eighteenth century fabric in the house, possibly from two phases, but there is no further information.

See also: Alva House, Clackmannanshire and Johnstone Mausoleum, Alva Churchyard, Clackmannanshire.

Literature: A.T. Bolton, The Architecture of Robert and James Adam, Volume II, Index, 1922, p. 9; D. King, The Complete Works of Robert & James Adam and Unbuilt Adam, Volume 2, 2001, p. 124; D. L. Prior, ‘Johnstone, John (1734-1795)’, Oxford Dictionary of National Biography, 2004, online [accessed 05 December 2023]; Historic Environment Scotland, ‘Denovan House, Dunipace’, Listed Building Description, online [accessed 6 December 2023]

Louisa Catt, 2023