An optical fibre connector system, including an optical connector disposed therein, and a recess allowing a through connector to be connected to the optical connector. The optical fiber connector system includes an engagement mechanism that acts on the optical connector to prevent release of the through connector when connected to the optical connector, and which is operable to enable release of the through connector. The engagement mechanism is a movable element that normally engages the connector to the support and which can be moved to disengage the connector from the support, thereby releasing the through connector.