An early half-plan of the west end of the Great model. Drawn probably by Wren; trimmed at the top through the wall on the west return face of the main body. Datable 1673. Implied scale, c.12 ft to 1 inch.
The fine ruled and freehand ink technique over neat pencil under drawing suggests Wren's hand rather than Woodroofe's. The plan belongs to an initial phase in the development of the design from the Greek Cross scheme in early 1673 and represents only a third of the length of the model. The west portico is in an arcuated system of three-quarter columns set on piers. Pilasters behind the piers answer to pilaster responds on the rear portico wall and imply a beamed or barrel vaulted vestibule. An opening in the north flank wall of the vestibule leads to a grand, curve-ended, open-wall staircase, which rises in at least four flights via half-landings to an upper stage, presumably at attic level, above the portico vestibule.
The western range in this design probably represents the addition of the 'library body and portico' to the design of the model recorded by Robert Hooke in early February 1673. The use of engaged rather than freestanding columns across the west front allowed Wren to continue the wall upwards above an entablature in an attic storey. This same articlation of three-quarter columns on an arcuated wall (with alternate arched windows and niches) occurs on a preliminary elevation for a transept wall or east wall of the Great Model at All Souls. The scale indicated that the columns and pilasters would have been 4 ft in diameter. The arches of the portico would have been 10 ft wide in the outer bays and 12 ft in the centre, a bay system which replicates that in the All Souls elevation.
A ceremonial west door gives access to a large, cross-vaulted vestibule, approached by steps and doors on both sides. It would have provided public access from Paul's Alley, the historic north-south route through the precinct which crossed the nave of the pre-Fire cathedral via the north and south nave doors. It survives today as a narrow yard on the west side of the present chapter house. In the completed design the vestibule is surmounted by a dome.