A locking tongue has a base part, a webbing slot in the base part and a locking cam. The locking cam is movable between a rest position and a clamping position. A biasing means biases the locking cam towards the rest position. The locking cam can assume the rest position in which the belt webbing can pass freely through the webbing slot, a clamping position in which the locking cam presses the belt webbing against the clamping edge of the webbing slot, the biasing means being able to return the locking cam from the clamping position into the rest position, and a locking position in which the locking cam locks the belt webbing in the webbing slot, the biasing means not being able to return the locking cam from the locking position towards the rest position.