The 'four-block' scheme (for which there are no drawings at Sir John Soane's Museum) is known from a single large plan at All Souls College, in two joined sheets (Geraghty 2007, no. 196). The All Souls plan is a reduction of the seven block scheme by three wards to bring the plan within the boundary of granted site. It was probably prepared towards the end of 1695, immediately before the approved scheme with its blocks of three parallel ranges. It can be dated after a meeting of the Grand Committee of the Commissioners on 30 September, at which it was decided to urge the Commissioners to ask the king for the grant of additional land to the south and west of the approved of February that year, a request that must have been rejected by December 1695 when steps were being taken to appoint further sub-committees and finalise the design for approval by the king. The final design [5] was approved by the Fabric Committee in January 1696. However, this could have remained current in the early months of 1696, before the the approval of the three-block scheme on 29 April 1696.

The 'four-block' scheme marks the first appearance of the famous colonnades of paired columns. Four parallel ranges are linked by single-storey colonnades of paired columns that run either side of the central avenue, returning around the north ends of the two hall blocks for five bays, but without a corresponding return at the south end. At this end the colonnades are open, forming entry points to long corridors that link the wards and provide routes to the two hall blocks at the northern ends. These hall blocks are set very close to the King Charles II Court and its pendant on the east, precluding entry to the hospital from the west or east sides. The four-block scheme was a utilitarian reduction of the seven-block scheme, aimed at maximising accommodation within the land between King Charles II Building and the south boundary, while also providing hall and chapel ranges. The wards are narrower than those in the seven-block scheme, more closely spaced, and the two northern hall blocks are not designed to carry domes (the eastern hall was only designated as the chapel much later in the design process). The plan presents the base blocks of the King Charles and pendant ranges in an unresolved form, without subdivision into wards and with significant differences in plan, suggesting an initial outline scheme rather than a detailed proposal.