Grain Fort, built between 1861 and 1868, performed a central role in the Grain Fortifications; one of five artillery bastions built on the Isle of Grain from the mid 19th century onwards. The others were Grain Tower [TQ 87 NE 7], The Dummy Battery [TQ 87 NE 10], the Wing Battery [TQ 87 NE 9] and the Grain Battery [TQ 87 NE 1026]. Construction work on Grain Fort began after the 1860 Royal Commission into England's Coastal Defences. The report recommended that a large fort and auxiliary battery be built at Grain and that Grain Tower be strenghened and re-armed. Lack of funds left the Tower virtually unchanged. The Fort was designed as a garrisoned and defensible semi-circular keep, surrounded by a polygonal earthwork, on top of which a 'terreplein' had gun emplacements. Behind the gun emplacements ran a fighting platform, while the main magazine for all the fortifications at Grain was located below the bank. The auxiliary battery built between 1867 and 1869 was named Grain battery and subsequently renamed Dummy Battery in 1901. It was linked to the Fort via a road carried in a cutting and a causeway [TQ 87 NE 118]. Grain Fort was rearmed at the turn of the twentieth century, when it formed part of the front line of defence for the Thames and Medway estuaries. It continued to serve as a heavy gun emplacement throughout the second world war. The military abandoned the site in 1956. Between 1961 and 1975 the apperance of the fort was substantially altered. The keep was completely removed and the site was partially infilled and levelled off. The field survey report uses original maps and on-site observations to detail the keep, the earthwork and the 'terreplein' and its emplacements [13].