This is back slang taken from the name Allen, of building firm Allen and Norris, who laid out this road sometime around 1911. William Gilbert Allen was born in 1869, as a child his father, also a builder moved his gamily to Fulham from Bedfordshire. William set up his the business in 1889 just as Fulham Vestry was in the process of firing the starting gun for a housing boom in its district. The firm had already built a number of large estates in and around the local area, including at Battersea and Wandsworth, by the time they came to develop Crabtree Lane, indeed it was to be the firm’s last great venture. These properties were aimed at “Clerks and Artizans” and would be furnished kitted in identical fashion, with fittings bought in bulk. They would have a stove, blinds on the front windows, tiling in several areas, mantelpieces in the main rooms, and a porcelain (not iron) bath. Back slang was a surprisingly popular idea for street names among developers at around this time. It is thought back slang originated in the Victorian period, being used mainly by market sellers to have private conversations behind their customers’ backs and pass off lower quality goods to less observant customers. Today yob is probably back slang’s best known addition to English.