Betchworth Fort: a London mobilisation centre
Heritage Category: Scheduled Monument
List Entry Number: 1020370
Date first listed: 24-Nov-2000
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This copy shows the entry on 16-Jan-2019 at 23:22:04.
The building or site itself may lie within the boundary of more than one authority.
District: Mole Valley (District Authority)
National Grid Reference: TQ 20068 51485
Legacy Record - This information may be included in the List Entry Details.
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.
Legacy Record - This information may be included in the List Entry 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
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
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.
The contents of this record have been generated from a legacy data system.
Legacy System number: 32277
Legacy System: RSM
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
Beanse, A and Gill, R, The London Mobilisation Centres - unpublished gazetteer, 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