The vault designs largely follow those Soane produced for St Peter's Walworth (SM 54/6/12), and Holy Trinity, Marylebone (SM 54/4/1). The vaults are accessed by internal staircases in the front end bays, and an external staircase from the rear allowed burials to be brought in from outside (see SM 47/5/9, SM 47/5/12). St Peter's used two staircases on each side, and at Holy Trinity, a winch mechanism was devised as space was limited (SM 54/4/29). The first drawing in the scheme for St John's even has a pencil outline of a coffin within one of the niches by the rear entrance (SM 47/5/56).