Grid framework structure

A grid framework structure comprising:

• i) a first modular storage unit frame arranged to define a first storage volume when assembled for the storage of a plurality of stacks of containers,
• ii) a second modular storage unit frame arranged to define a second storage volume when assembled for the storage of a plurality of stacks of containers, wherein the first modular storage unit frame and the second modular storage unit frame are configured to be arranged together to define a storage volume comprising the first storage volume and the second storage volume,
• iii) a grid structure comprising a first set of grid members extending in a first direction and a second set of grid members extending in a second direction, the first direction being substantially perpendicular to the second direction to form a grid pattern comprising a plurality of grid cells,
• wherein the grid structure is mounted to at least one of the first modular storage unit frame and the second modular storage unit frame such that each of the first modular storage unit frame and the second modular storage unit frame supports a plurality of grid cells so that, in use, a load handling device operative on the grid structure is able to retrieve a container from the storage volume.