Some embodiments are directed to a surgical robotic system for use in a surgical procedure, including a surgical arm having a movable arm part for mounting of a surgical instrument having at least one degree-of-freedom to enable longitudinal movement of the surgical instrument towards a surgical target. Some other embodiments are directed to a human machine interface for receiving positioning commands from a human operator for controlling the longitudinal movement of the surgical instrument, and an actuator configured for actuating the movable arm part to effect the longitudinal movement of the surgical instrument, and controlled by a processor in accordance with the positioning commands and a virtual bound. The virtual bound establishes a transition in the control of the longitudinal movement of the surgical instrument in a direction towards the surgical target. The virtual bound is determined, during use of the surgical robotic system, based on the positioning commands.