Leonard Martin was born in London, England on 12 July 1869 and was also articled to the firm Giles Gough & Trollope in London. He also He attended the National Art Training School in South Kensington, London, and Lambeth School of Art in London. At Giles Gough & Trollope he met Henry John Treadwell (1861-1910) with whom he went into partnership in 1890. The partnership closed following the death of Treadwell in 1910. From 1929 onwards Martin was in partnership with E. C. Davis. In 1912 Martin, in collaboration with Sydney V. Kendall, won the competition for the Bain Avenue Housing Project in Toronto, Ontario, Canada.
Martin's address was given as The Lych House in Cobham, Surrey in 1902 and 1905; 2 Waterloo Place, Pall Mall. London [possibly address of office] in 1902; and Seymour House, Waterloo Place, Pall Mall. London [possibly address of office] in 1914 and 1926.
Martin exhibited at the Royal Academy in London between 1912 and 1929. A watercolour drawing of a house at Worplesdon, designed by Martin is illustrated in 'The Studio Yearbook of Decorative Art' 1913 (p.53); and a photograph and ground- and first-floor plans of a house at Berkhampstead, Herfordshire, by him is illustrated in 'The Studio Yearbook of Decorative Art' 1915 (p.95).
Martin died in Surrey in 1936
Works by Treadwell & Martin included the rebuilding and later addition of St. John's School, Leatherhead, Surrey (1890s); St. Mary's Hospital 'later Children's Hospital], Carshalton, Surrey (1890s); Cottage Hospital, Cobham, Surrey (1890s); Scott's Restaurant, 18-19 Coventry Street, London (1892-94); Rising Sun public house, Tottenham Court Road, London (1897); St. John's Hospital in Lisle Street, London (1897-1904); Old Shades public house, Whitehall, Westminster, London (1898); Furness office building, 60 St. James's Street, London (c.1900); 7 Hanover Street, London (c.1900); Panton House, Haymarket, London (c.1900); office building, 74, New Bond Street, London (c.1900); office building, Whitehall House, Whitehall, Westminster, London (1904); Sandroyd School, Cobham, Surrey (1905-06); 78 Wigmore Street, London (1906); office building, 106 Jermyn Street, St. James, London; 78-81 Fetter Street, Holborn, London (c.1906); office buildings, 55 and 20 Conduit Street, Mayfair, London (1907); office buildings, 23 Woodstock Street and 7 Dering Street, London (1907). Other buildings by the partnership included Joyce Green Hospital in Dartford, Kent; the Southern Hospital in Carshalton, Surrey; several public houses and breweries, including the Black Swan in Carter Lane, London, and the Old Dover Castle in Westminster Bridge Road, London; hotels, including Shelley's Hotel in Albermarle Street, London; churches, including the Presbyterian Church in West Norwood, the Holy Trinity Mission Church at Tulse Hill, London, and St. John's Church at Herne Hill in Surrey.
Photographs of the entrance hall of 'Pyports' in Cobham, Surrey, a dining room fireplace at Cobham, and the drawing room and dining room fireplaces at 'The Lych Gate House', Cobham, designed by Treadwell & Martin, are illustrated in 'The Studio Yearbook of Decorative Art' 1907 (pp.74, 113, 114, 115).
Directory of British Architects 1834-1914. Compiled by Antonia Brodie, et al. Volume 2: L-Z. London; New York: British Architectural Library, Royal Institute of British Architects/Continuum, 2001
Gray, A. Stuart. Edwardian architecture: a biographical dictionary. London: Gerald Duckworth & Co., Ltd., 1985
‘Obituary’. RIBA Journal vol. 43, March 7 1936 p. 498