Having finished his training in 1902, Binnie joined his father's engineering practice working primarily in
water supply and
hydro-electric power. He was made a partner of the firm in 1904 and a senior partner upon his father's death in 1917. His work included projects in
Birkenhead,
Belfast,
Oxford,
Kano, Singapore and
Rangoon. Binnie served as the technical advisor to the British representative on the
Central Commission for Navigation on the Rhine in 1922; as a member of the
Great Ouse Drainage Commission in 1925 and of the
Doncaster Area Drainage Commission in 1926. He worked on several projects involved with the
River Nile in Egypt, acting as a commissioner for the heightening of the
Aswan Dam during 1928 and advising on
hydro-electric power generation possibilities on the river in 1937. Binnie was known for his extensive travels to see projects first hand. In 1940, at the age of 72, he travelled to Hong Kong to advise on a dam and reservoir project. During his return flight to France on a French airliner, France was
overrun by German forces and the pilot diverted to
Algiers to disembark the passengers. Left without any means of transport in an unfamiliar country that was soon to become hostile, Binnie was forced to work for his passage home. He signed on as an assistant to a Chinese cook aboard a
collier bound for
Gibraltar whose Turkish crew had mutinied and left the ship shorthanded. He eventually returned safely to Britain where he saw out the rest of the
Second World War. == Professional institutions and honours ==