Widnell was established in 1852, by Frederick Widnell and Charles Trollope, to provide services on London's booming property development work. The practice expanded in the following years to include cost consultancy work on engineering and infrastructure projects and by the turn of the 19th century had become established as one of the leading firms of quantity surveyors

International operations began in the 1940's with branch offices established in the Caribbean and the Middle East. Expansion continued in the 1970's in Australia and Africa and in the 1980's with commissions in Europe and South East Asia. Widnell Hong Kong was established as a separate practice in 1977 and now employs 200 staff in offices in Hong Kong, Beijing, Shanghai, Chongqing, Chengdu and Shenzhen and an affiliate office in Macau.