Queenborough Lines is a 19th-century defensive linear earthwork protecting the southern flank of the Royal Naval dockyard and town of Sheerness from land attack. The report of the Royal Commission on the Defences of the United Kingdom (1860) recommended the construction of advanced works outside Mile Town, Sheerness, 'either immediately outside that suburb or on a range of hills at some distance from the place'. The latter was recommended 'c.3500yds in advance of the present (Sheerness) lines'. In fact the Lines run across Minster Marshes which separate Queenborough and Minster and provided a land defence for Sheerness. Property was acquired and vested in the Secretary of State for War. Clearance Rights were purchased under the Defence Act 1860. Expenditure to 30 June, 1868 had reached £18,586. A further £320 was needed to complete the work. The Defence Committee Report (1869) indicated that proposed batteries at Cheyney Rock and Queenborough at either end of the Lines had not yet commenced. At the extremities of the line it was intended to construct a tower for a two-gun turret which would strengthen the weak points of the line. An alternative plan was for positions for three guns on Moncrieff mountings instead of each two-gun turret.