In 1845, the Royal Society decided to build a separate house for the head gardener, possibly to make up for the relatively low salary. Designed by the colonial architect, William Porden Kay, it was situated near the northern end of the Arthur Wall and initially had two rooms and a kitchen downstairs with a steep stairway to a small attic.
When the entrance gates were installed in 1878, the building became known as the Gatekeepers Cottage. It has since functioned as a porter's lodge and tea rooms, and administration offices.