Summarised from report:

Four stair shafts descended from the Inner North-West Bastion to underground galleries. These independent shafts and galleries provided access to several groups of casemated gunrooms that defended the ditches of the bastion. The building of independent galleries meant that an attacking force could not take the whole bastion if one part was captured. One gallery served the Inner North-West Bastion Casemates, a second led to the Centre North-West Bastion Casemates, a third communicated with the Left Flanking Casemates, while the fourth served the Right Flanking Casemates, the Counterscarp Gallery and Casemates, as well as the Guard Room of the Centre North-West Bastion. The easternmost shaft is 2.34m in diameter with a central stone newel. The galleries leading from it are lined with brick in English bond, usually whitewashed, with paved brick or plain chalk floors. (1)

Detail of these structures appears on a plan dating to 1871 which shows all of the works which were undertaken under the reccomendations of the Royal Commission though these likely pre date the plan by over 50 years, this is the first clear depition of them. (2)

<1> English Heritage, 2004, The Western Heights, Dover, Kent: Report No. 2: The Citadel (Unpublished document). SKE17690.

<2> Captain H S Palmer (?), 1871, War Department OS 1:2500 Sheet LXVIII.15, revision of 1871, annotated with positions of magazines in the Citadel in 1877 (Map). SKE51524.