overlooking
Guildford in
Surrey, showing its commanding position high on the
North Downs. 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. Thirteen sites were chosen, at
Pewley Hill, Henley Grove, Denbies,
Box Hill,
Betchworth,
Reigate,
East Merstham, Fosterdown,
Woldingham,
Betsom's Hill,
Halstead,
Farningham and (to the northeast of London)
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. The intention was that the centres would, in addition to holding ammunition and other supplies, act as strong points in an almost continuous line of field fortifications. The trench lines joining the Defence Positions could be rapidly excavated on the outbreak of war. 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 used by
DSTL. 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. North of the Thames, the line was continued to the
River Lea at
Broxbourne rather than stopping at
Epping. South of the Thames, it was continued to
Halling, via
Wrotham, linking to the
Chatham defences. At the western end the line was stopped short at Buckland Hill, just beyond Reigate Fort. At Guildford, houses have been built on the Pewley Hill site, but
Henley Fort (aka Henley Grove) has been well preserved as a youth education centre. It could be seen on a Heritage Open Day. == Reigate Fort ==