Horsley was the son of the painter
John Callcott Horsley. He was articled to
Norman Shaw from 1879 to 1882, and in 1883 became his assistant. From 1884 to 1885 he was assistant to
John Dando Sedding. In 1883, Horsley was a founder member of the St George's Art Society, 1884 of the
Art-Workers' Guild. He was the first recipient, in 1887 and again in 1888, of the
Owen Jones Studentship of the
Royal Institute of British Architects (RIBA) which took him twice to Italy. A RIBA associate in 1890, he left the institute in 1892 in protest against plans for compulsory registration of architects; he rejoined as a fellow in 1906. From 1911 to 1913, Horsley was president of the
Architectural Association. ==Works==