London Defence Positions

The line to be followed by these entrenchments was supported by thirteen permanent small polygonal forts or redoubts called London Mobilisation Centres, which were equipped with all the stores and ammunition that would be needed by the troops tasked with digging and manning the positions.

Following a number of proposals by senior military figures, an 1888 memorandum written by Colonel John Charles Ardagh envisaged a scheme of simple earthworks for infantry and moveable armaments, intended to be dug and manned in an emergency by the Volunteer Force, the line being supported by permanent works, the London Mobilisation Centres, at 5 mile (8 km) intervals, which acted as stores and magazines.

The London Defence Scheme was announced in Parliament in March 1889 by the Secretary of State for War, Edward Stanhope, by which time the 13 sites for the Mobilisation Centres had already been purchased at a cost of £25,000.

[1] The London Mobilisation Centres were built along a 70-mile (113-kilometre) stretch of the North Downs from Guildford to the Darenth valley and across the River Thames in Essex.

During World War I, part of the London Defence Positions scheme was resurrected to form a stop line of trenches, in case of a German invasion.