Abstract: A mortice and tenon joint of two structural members which avoids the protrusion of the tenon beyond the mortice. Across the tenon (11) of one member (10) there is cut a dovetail aperture or slot (12), and a movable tapering wedge (16) of similar dovetail cross-section is slidably housed within a tapering channel also of similar dovetail cross-section which crosses the mortice (14) of the other member (13) such that when the tenon (11) is inserted wholly into the mortice (14) the wedge (16) may be driven along the tapered channel to become firmly engaged within the dovetail aperture or slot (12) thus to lock the members (10, 13) together and prevent them from separating until the wedge (16) is withdrawn.