A tongue for a motor vehicle seat belt restraint system providing high friction restraining belt webbing transfer through the tongue in an impact condition. The tongue incorporates a deformable element which maintains the webbing away from contact with high friction elements in the normal use of the belt system. In a crash condition in which significant tension loads are applied to the belt webbing, the deformable element yields to provide contact between the belt webbing and a high friction surface which restricts the transfer of the webbing from the shoulder belt portion of the webbing to the let belt portion of the webbing which is normally more highly loaded in an impact condition. Several embodiments of deformable elements are described.