Betchworth Fort: a London mobilisation centre

Reasons for Designation

The 15 London mobilisation centres, constructed during the 1890s, formed part of a comprehensive military scheme known as the London Defence Positions, drawn up in 1888 to protect the capital in the event of enemy invasion. The scheme was a response to the rapid progress made in warship production by France and Russia during the early 1880s, which had led to official doubts about the Royal Navy's defence capability. Essentially a contingency plan, it provided for the establishment of a 72 mile long, entrenched stop-line divided into ten tactical sectors and supported by artillery batteries and redoubts. The planned stop-line ran from the southern edge of the Surrey and Kent Downs, up the western side of the Darenth Valley to the Thames, and then north westwards through Essex from Tilbury Fort to Epping. Although the stop-line and main defence positions were not to be established until an invasion was imminent, it was thought prudent to build a series of mobilisation centres, 13 on new sites, along the projected course, either for artillery deployment or where troops could assemble and collect tools and supplies. By 1905, official confidence in the Royal Navy had been restored, and the now obsolete mobilisation centres were abandoned and gradually sold off. No two mobilisation centres are exactly alike, and a broad distinction can be drawn between the four centres purpose built for artillery deployment, and eight which functioned as infantry positions. However, in general terms there are close similarities: each, for example, was typically enclosed by a rampart, ditch and spiked fence, containing a partly earth-sheltered, reinforced concrete and brick built magazine and stores. Beyond the main compound were associated buildings of a standard type, including a brick caretakers lodge and a large, barn-like tool store. Most mobilisation centres have been the subject of subsequent alteration and/or reuse. As a short-lived and rare monument type, all mobilisation centres with surviving remains sufficient to give a clear impression of their original form and function are considered to be nationally important.

Unusually for this type of monument, Betchworth Fort has remained largely free of alteration or renovation, and despite the conversion of the casemates for accommodation, the chambers remain substantially intact, and the magazine survives unmodified. It retains evidence relating to the construction and use of the mobilisation centre, as part of the strategic defence of the capital, at the start of the 20th century.

Details

The monument includes the main compound of Betchworth Fort London mobilisation centre, situated on a chalk ridge of the Surrey Downs on the southern outskirts of Box Hill village. The east-west aligned, roughly semi-circular compound, is defined on its southern front by a crescent shaped earthen rampart. The outer ditch contained spiked metal railings, known as a Dacoit fence, which extended to the rear, or gorge, of the centre, completely enclosing the compound. The north facing gorge, approached by a track from the west, was made defensible by a row of five projecting casemates, with rear facing doors and windows still retaining their loopholed metal shutters. Flanking concrete walls, pierced by loopholes, extend to meet the ends of the rampart. Access to the interior was through two stout metal doors in the gorge walls, which opened onto a small courtyard on either side of the casemates. The top of the rampart, revetted on its inner edge with flint, is accessible from each courtyard, and was designed to function as a firing parapet, allowing the mobilisation centre some degree of self-defence in the event of enemy bombardment. The courtyards are linked by a sunken, covered corridor between the casemates to the north and the three roomed magazine block set into the rear of the rampart, or blast-bank, to the south. Small chambers, designed for the storage of lamps, fuses and tubes, are located at ground level, at each end of the magazine passage. Within one of these chambers, the original fuse and tube locker survives in place. To minimise the risk of explosion, the magazine chambers were lit by lamps set in recesses behind panes of glass, and accessed from the lamp passage which surrounds the magazine. The lamp passage opens onto the corridor in front of the chambers, which also contained a shifting lobby, where magazine personnel changed into protective and non-spark producing clothes, before entering the cartridge store. The magazine retains many of its original features, including the lamp recess casements and original notices labelling various components of the magazine. Following the abandonment of the London Defence Positions, the site was sold in 1908. The chambers of the casemates were subsequently converted for accommodation and were occupied for much of the 20th century. During this period, double doors were added to the eastern end of the magazine passage, and chimney stacks were constructed over the air vents in the flat, concrete roof. Associated with the main compound are the original, semi-detached pair of caretakers' cottages, situated along the western approach road, around 100m west of the compound. The cottages have been converted into a private residence, and are therefore not included in the scheduling. A mobilisation tool store usually accompanied the caretakers' cottages, outside the main installations, although this is absent at Betchworth Fort. The modern, wooden chalet constructed within the western portion of the ditch, is excluded from the scheduling, as well as the small chalet within the eastern courtyard and the structures along the southern edge of the ditch. A number of other features within the area of the monument are excluded from the scheduling. These are: all modern fixtures and fittings, including components of the modern electricity and plumbing systems, as well as modern materials and equipment stored within the mobilisation centre. The ground beneath these items is included in the scheduling, together with structures and surfaces related to the military use of the site, to which some of these features are attached.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 2 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.

Legacy

The contents of this record have been generated from a legacy data system.

Legacy System number:

32277

Legacy System:

RSM

Sources

Books and journals
Smith, V, Post-Medieval Archaeology in Chatham and London: The Changing Face of English Land Fortification 1870-1918, Vol. 19, (1985), 105-149

Other
Beanse, A and Gill, R, The London Mobilisation Centres - unpublished gazetteer, 1999,

End of official list entry

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