Fort Farningham: a London mobilisation centre


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:


Ordnance survey map of Fort Farningham: a London mobilisation centre
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The building or site itself may lie within the boundary of more than one authority.

Sevenoaks (District Authority)
National Grid Reference:
TQ 53309 66893

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, Fort Farningham has remained largely free of alteration or renovation and, despite the infilling of the ditch, survives comparatively well and will retain evidence relating to the construction and use of mobilisation centres, including the tunnels beneath the rampart which are unique to Fort Farningham. The construction of an Royal Observer Corps nuclear Monitoring Post within the perimeter ditch, illustrates the renewed significance of this location during the Cold War period.


The monument includes the main compound of Fort Farningham London mobilisation centre, and a later, Royal Observer Corps underground Monitoring Post. It is situated on high ground above the River Darent, around 1.5km west of Farningham. The north east-south west aligned, roughly semi-circular compound, is defined on its south eastern front by a large, crescent shaped earthen rampart. The surrounding ditch was infilled during the second half of the 20th century, and partly damaged on its south western side by construction of a house, but will survive for much of its length as a buried feature, around 20m in width. The ditch contained spiked railings, known as a Dacoit fence, which extended to the rear, or gorge, of the centre, completely enclosing the compound. The north west facing gorge contains a sunken roadway which is approached from the main access road by a vehicle ramp at its northern end, and was made defensible by a row of three, slightly projecting casemates, with the rear facing doors and windows still retaining their loopholed, metal shutters. Flanking concrete walls extend to meet the ends of the rampart. Access to the interior is through a break in the southern gorge wall, protected by stout metal doors which open onto the southern one of two courtyards flanking the central casemates. The top of the rampart and gorge wall can be reached by concrete steps from each courtyard and could therefore act as a musketry parapet, allowing the mobilisation centre some degree of self-defence in the event of enemy attack. The surrounding ditch could also be accessed from each courtyard by way of a tunnel, labelled `covered way', which led out through the rampart from a casemate at the rear of each courtyard. The courtyards are linked by a covered passageway which runs through the central casemates and the three roomed magazine block, which is partly covered by the earthen rampart, or blast-bank. 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 corridor in front of the chambers contained a shifting lobby, where magazine personnel changed into protective and non-spark producing clothes. Many of the original fittings survive, including the lamp recess casements and some of the original notices labelling various components of the magazines. Buried within the north eastern section of the infilled ditch, is an underground bunker, constructed and used during the 1960s by the Royal Observer Corps. This Monitoring Post formed part of the UK Warning and Monitoring Organisation and belonged to a network of such posts, designed to record the location, height and power of a nuclear explosion and to monitor radioactive fallout. The surface monitoring devices have been removed, although above-ground remains include the air ventilator and the top of the vertical access shaft. The buried chamber, designed to accommodate a crew of three, is likely to retain many of its original features. Associated with the main compound are the original, semi-detached pair of caretakers cottages and the mobilisation tool store, situated on either side of the north western approach road, outside the perimeter ditch. The cottages are now occupied as private residences and the tool store has been converted for business use, and these buildings are therefore not included in the scheduling. Part of the ditch in the south west has been damaged by past modern construction of a house and associated landscaping, and this area is also not included in the scheduling. In addition to the boiler shed, and associated components, on the south western edge of the rampart, a number of features within the area of the monument are excluded from the scheduling, these are: all modern fences and hedging; the Ordnance Survey trig point and the temporary wooden structure located on top of the rampart; all modern fixtures and fittings, including components of the modern electricity 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 the 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.


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

Legacy System number:
Legacy System:


Books and journals
War Office, , Fort Farningham design plan, (1899)
Wood, D, Attack Warning Red. The ROC and the defence of Britain 1925-1992, (1992)
Beanse, A, Gill, RJ, 'The Redan (Palmerston Forts Society)' in The London Mobilisation Centres, , Vol. 43, (1998), 12-24
Smith, V, 'Post-Medieval Archaeology' in Chatham and London: The Changing Face of English Land Fortification 1870-1918, , Vol. 19, (1985), 105-149
Beanse, A and Gill, RJ, Farningham Mobilisation Centre, 1998,
Beanse, A and Smith, VTC, Re: Discussion of outer earthworks shown on 1899 design plan, (1999)
Smith, V, (1999)


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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