The sites were purchased from the trustees of the Hope estate by the Ministry of Defence in 1891, and construction began in 1899. The two centres were laid out in the form of infantry redoubts typical of the period, but also included magazines (partially below ground level) for the storage of shells and cartridges. (In common with the majority of the eleven other mobilisation centres, the forts were designed for the use of the infantry only and the stored ammunition was intended for the use of mobile field artillery which would be deployed nearby as required.) The main flat-roofed buildings were built in brick and reinforced concrete and were protected from artillery fire by crescent-shaped earth blast banks, surrounded by an outer ditch.