The Chatham, Brompton or Great Lines, an C18th land defence system surrounding Chatham dockyard and barracks. The first phase, started during the Seven Years War in 1755 and completed by 1757, consisted of a series of unrevetted ditches and bastions running from Ordnance Wharf eastward around the dockyard and back to the Medway, enclosing Brompton, in total c. 3 km in length. Though a cheap option for the period, the ditches, 8 feet deep and 27 feet wide, and the earthen rampart, 9 feet high, survive largely intact. The defences included a number of key components - Cumberland's Line, Prince William Bastion, Princes of Wales Bastion, Kings Bastion, Prince Edward's Bastion, Prince Henry's Bastion, Prince Frederick's Bastion, Duke of Cumberland's Bastion and Ligioners Line. Provision was made for three gates. One, close to the later Fort Amherst (TQ 76 NE 395), carried the road from Chatham. The remaining two were in the eastern flank between Prince Henry's and Prince Edward's bastions and between Prince Edward's and King's bastions.

Within a few years of the war the fortifications were in a poor condition. Upon the outbreak of the American War of Independence (1779) proposals for reinforcement were developed. Although not all were carried out a number of improvements were made. Some of the bastions were revetted in stone and the parapets were reformed. New gun platforms were constructed as well as a new magazine and sally ports. Within the defended area Townshend's redoubt in the north and Amherst redoubt in the south were constructed. Prince William's bastion was advanced into the field of fire and Belvedere Battery was built. The Couvre Porte between Prince of Wales and King's bastions was built.

During the 1780s and 1790s a number of minor modifications were made but by 1798 the defences had again fallen into a poor state. From 1803 the threat from France provoked a period of great investment in fortifications across the UK and this included the third and final phase of construction at Chatham. From 1803-1815 Chatham was reinforced as a fortress capable of withstanding a siege. The programme of construction included additional fortifications, two new sets of barracks, military hosptials, magazines and extension to the Gunwharf. The main focus of the defensive improvements were a new magazine in a ravelin between Prince Frederick's bastion and the Duke of Cumberland's bastion, revetment in brick of all scarps and parapets, a hornwork at the Couvre Porte, the completion of Fort Amherst and a new barrier ditch above the Gunwharf. A new set of defences was created at the Gillingham end of the defended area called the Lower Lines. (14)

By the end of the Napoleonic Wars their military importance had declined. Fort Amherst was declared obsolete by the 1860 Royal Commission. Much of the additional work remains but it is extremely overgrown. At the N end Townshend's Redoubt has largely disappeared. In 1981 a registered charity, The Fort Amherst and Lines Trust, was set up and in 1982 fourteen acres of the defences were purchased from the DOE. Scheduled, (Hornwork at the 'Couvre Port' not included). (3-5).

The Medway Military research Group has continued its heavy involvement with Fort Amherst; carrying out the majority of excavation work into the spoil heaps and shafts within the Fort's tunnels. These excavations have unearthed coins and ammunition. A major discovery of the Group was that of the main underground magazine of the Fort, in Belvedere Battery. (6)
Note on a scheme to restore Fort Amherst. (7)
Additonal bibliography [8,9].
Photo survey [10].
See also [11]
Topographic Survey [12]

A report on evolution of the Spur Battery area of Chatham Lines from 1633 to the present day was produced by Historic England in 2016 to "assist in helping to understand how the place has developed and been used over the last 300 years" as works are planned "to return the site to a good condition and to beneficial use" (13)

"The first phase of the Chatham Lines as constructed during The Seven Years War (1756-63)". An 1786 "plan has the first use of the name Spur Battery here referring to the new length of fortification built between Prince of Wales bastion and Prince Williams bastion, sticking in out into the field of fire to form what is known as a spur." (13)

Historic england archive material (15)

<01> OS 1:2500 1969 (OS Card Reference). SKE48211.

<02> DOE(IAM) AMs Eng 2 1978 111 (OS Card Reference). SKE41413.

<03> DOE(IAM) Record Form Plan (OS Card Reference). SKE41446.

<04> Kent Arch Rev 68 1982 172-4 (OS Card Reference). SKE45805.

<05> Handbook of Kent's Defences 1540-1945 1977 (D Bennett)10-14 (OS Card Reference). SKE43671.

<06> The Medway Forts 1976 (KR Gulvin) 7 8 (OS Card Reference). SKE50417.

<07> Kent Arch Rev 74 1983 82 (GM Harvey) (OS Card Reference). SKE45818.

<08> Kent County Council, 1999, Survey of Kent post-1500 defence sites, KD73 (Index). SWX11828.

<09> Kent Arch Rev 47 1977 158 (K Gulvin) (OS Card Reference). SKE45784.

<10> 1994, Photograph (Photograph (Print)). SWX11125.

<11> Victor Smith and Ron Crowdy, 1994, From Tudor Rose to Mushroom Cloud. The Gazetter of Defence Heritage Sites in the Kentish Part of the Thames Gateway. An Overview (Unpublished document). SKE12458.

<12> English Heritage
KCC ENGINEERING SERVICES LABORATORY GEOTECHNICAL GROUP, 2011, Prince Edward's Bastion, Chatham Lines, Kent: Topographic Survey Report (Unpublished document). SKE29505.

<13> historic england, 2016, The evolution of the Spur Battery area of Chatham Lines (Unpublished document). SKE31634.

<14> Peter Kendall, 2012, The Royal Engineers at Chatham 1750-2012 (Bibliographic reference). SKE51751.

<15> Historic England, Archive material associated with The Chatham Lines Sheduled monument (Archive). SKE54003.