An electromechanical actuator for use in a hydraulic braking circuit of a vehicle comprises an electric motor having a stator and a rotor, and a linear actuator that is located within the motor. The linear actuator comprises an elongate shaft having a screw part at one end carrying an external thread that extends along a portion of the shaft, and a fixing part at the other end shaft, the linear actuator further comprising a drive nut that surrounds the screw part of the shaft and is located at least in a retracted position inside an enlarged bore of the first portion of the rotor body, the drive nut being connected to the screw part through a set of balls that engage the threads of the drive nut and screw part, and the fixing part of the shaft includes a tapering portion that engages a complimentary tapering portion of the bore in the second portion of the rotor body.