Fort Borstal was built as an afterthought from the 1859 Royal Commission on the Defence of the United Kingdom, by convict labour.

[1] Fort Borstal was designed to hold the high ground southwest of Rochester, South East England.

[2] A 18 in (457 mm) gauge railway was built connecting the four Chatham ring forts of Borstal, Bridgewoods, Horsted and Luton.

A rope-worked incline led west from Fort Borstal down to a gravel pit and wharf on the River Medway.

[1] After many years' use as a pig farm and store for the nearby Young Offenders Institution it was sold in 1991 to a company hoping to make it a museum, but that proved unsuccessful and the fort has been converted into living accommodation.