A surgical robot 1 for manipulating an endoscopic surgical tool has a projecting shaft 15 for connection to an armature structure 7. An attachment unit 19 is coupled to the shaft and has a longitudinal axis substantially perpendicular to a longitudinal axis of the shaft and a free end for coupling to an armature structure such that a first arm 18 of the armature structure is offset with respect to the shaft of the robot. The coupling may be a ball joint which sits vertically below the shaft. The first arm of the armature structure may be connected to a second arm (24, figure 1) by a lockable joint (31) and the whole armature structure may be mounted on a side rail of an operating table (8). Adjustment of the armature is preferably manual whilst the surgical tool is controlled remotely via the robot.
