The 1859 Royal Commission on the Defence of the United Kingdom report on Britain's defences believed that London was practically undefendable, but the view in the 1880s changed the emphasis to schemes based on simple earthworks for infantry and moveable armaments. These London Defence Positions were to be earthworks to be thrown up in time of war, but backed up with magazines at 5 mile (8 km) intervals. On that basis the London Defence Positions were built along a 70 mile (113 km) stretch of the North Downs from Guildford to the Darenth valley. 13 sites were chosen, at Pewley Hill, Henley Grove, Denbies, Box Hill, Bletchworth, Reigate, East Merstham, Fosterdown, Woldingham , Betsoms Hill, Halstead, Farningham and North Weald. The design of each site varied, but they were never very elaborate, just a magazine and storehouses for the mobilisation of troops, with limited defences. Related stores were set up at Tilbury, Warley and possibly Caterham . They were quickly viewed as obsolete, and all were sold off in 1907, with the exception of Fort Halstead, now the MoD's explosives research department.

Houses have been built on Pewley Hill, near Guildford. Henley Grove has been well preserved as a youth centre, and could be seen on a Heritage Open Day. Reigate Fort is being restored by the National Trust.

External links

London Mobilisation Centres Gazeteer