Herbert Sidney Fleming was born in Bingley, Yorkshire, England on 9 January 1881. After attending Bradford Technical College in Bradford, Yorkshire from 1900 to 1903, he was articled to Frederick Musto for two years. He then worked as an assistant to W. Egerton in Erith, Kent [now south-east London]. He qualified as an architect in 1909 and later that year was elected an Associate of the Royal Institute of British Architects (ARIBA). He subsequently practised as an independent architect in London. During the 1920s Fleming was in partnership with William Joseph Kieffer (1888-1944) as Kieffer & Fleming.
Fleming's address was given as 34 Thanet Road, Erith, Kent in 1909; 52B Leyland Road, Lewisham, London in 1911; 70 Little Heath, Old Charlton, London in 1914; 48 Grosvenor Road, Westminster in 1923 and 1926; 83 Pall Mall, London in 1938; and 8 Millbank, City Of Westminster, London in 1939. He died in London in 1943
Directory of British Architects 1834-1914. Compiled by Antonia Brodie, et al. Volume 1: A-K. London; New York: British Architectural Library, Royal Institute of British Architects/Continuum, 2001
‘Obituary’. The Builder vol. 165, 16 July 1943 pp. 56, 75