The One Tree Hill Allotment Society, was we understand formed during the Second World War’s Dig for Victory campaign. When exactly is not clear, but it was likely very early on during WW2.
“At the outbreak of hostilities, local authorities were empowered to requisition unoccupied land without permission, It was estimated that there were 600,000 plots on requisitioned land occupied land with permission of the owner, and common land with permission of the minister lightly later, councils were authorised, to convert parks, playing fields, and ‘any other land in their possession’ for use as allotments” [http://allotmentresources.org/blog/dig-victory/]
At the time, the area between the allotment and the railway line was occupied by the Joseph Wells and Son “Albert” fireworks factory, which was originally built in 1876.
The factory employed 50 people and produced display and domestic fireworks, as well as ships’ signals, including rockets, flares and smoke rockets for drain testing. The factory closed in 1947 and moved to Dartford.
The fireworks site was then at some point taken over by the council as a Horticulture Depot. As the photo below shows, up until the mid-1960’s the site was tree free.
View from One Tree Hill c 1965
The site has been the subject of some interest over the years from artists, one a major piece of work in the late 2000’s by David Carr Smith called Allotment Improvisations.
More recently we have found that the site was painted by William Grealish as a student in the 1970’s; after a gap of 40 years he has resumed painting.