A surgical robotic system 300 comprises a surgeon console 304, a remote surgical robot 301,302, and a control unit 303. Surgeon-console 304 comprises a base connected to a hand controller 305,306 by an articulate linkage comprising a plurality of alterable joints. Surgeon-console 304 comprises a driver to move each joint； and a presence sensor 309 to sense the presence of a user's hand on the hand-controller 305,306. Control-unit 303 being configured to: receive user inputs from to manipulate the robot 301,302； receive concurrent inputs from sensors including the presence sensor 309； and responds to (i) the lack of a surgeon's hand on the hand-controller 305,306； and (ii) an external force additional to gravity acting on the hand-controller 305,306 by controlling the drivers to move the joints with a damped response in the external force’s direction. Presence sensor 309 may be a set of position sensors, each sensing a position of a joint, and from this set of joint positions, control-unit 303 determines the configuration of the linkage, and from subsequent sets of joint positions, determines motion of the linkage. Presence sensor 309 may be one of a capacitive sensor, an inductive sensor, an optical sensor or a pulse oximeter.
