Robotic vacuum cleaning system

A vacuum cleaning system comprises a robotic unit (4, fig 1) comprising a traction arrangement 72 which defines a ground plane and a docking interface for receiving a handheld vacuum cleaner, a handheld vacuum cleaner 6 configured to be docked with the docking interface, the handheld vacuum cleaner comprising a main body housing a vacuum motor for drawing air through a suction flow path defined by the robotic unit when docked with the docking interface. The main body of the handheld vacuum cleaner defines a longitudinal axis X, and comprises a pistol grip handle 12 extending therefrom in a direction that is transverse to the longitudinal axis, wherein, when the handheld vacuum cleaner is docked with the docking interface, the handheld vacuum cleaner is supported in a position and orientation such that the longitudinal axis of the vacuum cleaner is oriented generally vertically with respect to the ground plane, and the pistol grip is oriented generally horizontally with respect to the ground plane.