(Picture: Alamy)

 

The Elsan closet patented in 1924 incorporated a weighted ‘deflector’ to tip excrement into a bucket, which contained a formaldehyde-based chemical treatment. It was initially marketed to households and other locations without mains water and sewers, but also proved suitable for a range of other environments.

(Picture: Royal Air Force Bomber Command, 1939–1941 © IWM [CH 478])

 

This picture shows a crew member in the cramped rear fuselage of a Vickers Wellington of No. 75 (New Zealand) Squadron RAF during the Second World War; an Elsan chemical toilet is visible behind him. Because they didn’t need a water supply or connection to sewers, these toilets were handy in a range of situations during the war, including air-raid shelters and the Cabinet (now Churchill) War Rooms beneath the streets of Westminster.

(Picture: Maurice Savage/Alamy)

 

From the 1950s, when flushing toilets connected to mains sewers were increasingly installed in houses in Britain, domestic demand for Elsan closets declined. At around the same time, car-drawn caravans and motorhomes grew in popularity, creating another market for chemical toilets, which were also installed in commercial planes and trains. Even after airlines began fitting custom-designed toilets, Elsan continued to supply the chemicals that sanitised them. ‘Elsan’ is still widely used as a generic term for chemical toilet fluid. 

 

Interestingly, it was around this time – from the early 20th century – that the water-closet, and the room that housed it, began to be called a toilet or a lavatory. Previously, a lavatory had described a wash-bowl or place for washing; ‘toilet’ meant the act of cleaning and preparation. From the middle ages, the room (or more commonly outdoor structure) was known variously as a jakes, bog-house, privy, latrine, necessary house or, in northeast England, ‘netty’.

 

The word ‘loo’ was first recorded in this context in the early 20th century. There are various theories about its origin. Some suggest that it’s derived from the French lieu d’aisance, ‘place of ease’, possibly picked up by British troops from French counterparts during the First World War, or even from lieux à l’Anglaise, the French name for early water closets installed during the 17th and 18th centuries. Others think it may have been a play on Waterloo (‘going to the water closet’).