This is the former gateway to the warehouses and offices of the supply dept that handled food and rum, it opened in 1742. Two ornamented white stone arches linked by iron lampholder. Over each arch is an ox skull and garlands, and a hollowed medallion with intertwined anchors. In front of gateway are four 18th-c. cannons as bollards.
When cannons were no longer fit to be used on warships, they were buried breech-down to protect the brickwork of the gatehouse from damage by carts and other vehicles.
Slightly overside cannon balls were hammed into the bores to permanently seal them
The British Navy's Victualling Yard at Grove Street, Deptford. The navy's other victualling yards in Gosport and Plymouth were supplied from here. Such a major supply operation required more than warehousing, though, and there were also abattoirs, pickling houses, brewhouses, ship's biscuit works, a cooperage, a rum distillery, and mills on the 35-acre site.
England has also used a lot of captured French cannons as bollards around the docks and piers. Click the link, it's full of info about the locations