Cable anchorage comprising: a plurality of axial cylindrical channels in an anchor block, each channel for individually accommodating a strand of a cable, wherein the channel extends along the whole length of the cable anchorage between a first channel end, proximal to a running part of the cable, and a second channel end equipped with strand-immobilising device; and a seal element positionable at a predetermined axial location of an inner wall (29, 29') of the channel so as to provide a seal between the inner wall of the channel and the strand, when the strand is in the channel, said seal element comprising an elastic material; wherein the inner wall (29, 29') of the channel comprises an annular or cylindrical recessed region (27, 29'), longitudinally coaxial with the channel, for accommodating the seal element so as to retain the seal element at the predetermined axial location during an axial displacement of the strand in the channel, the sealing element being removably arranged in the recessed region (27, 29'), the cable anchorage being characterised in that: the seal element and the second channel end of the channel are formed such that the seal element can be introduced into the channel through the second channel end, the seal element and the inner wall (29, 29') of the channel are designed such that the seal element is axially displaceable inside the channel from the second channel end to the predetermined axial location, the seal element is elastically deformable to a compressed state, in which it has a radial outer dimension which is smaller than or equal to all diameters of the inner wall of the channel between said second channel end and said seal element, and the ratio of the axial length of the recess to the axial length of the sealing element is greater than 1.1 but less than 1.5. a plurality of axial cylindrical channels in an anchor block, each channel for individually accommodating a strand of a cable, wherein the channel extends along the whole length of the cable anchorage between a first channel end, proximal to a running part of the cable, and a second channel end equipped with strand-immobilising device; and a seal element positionable at a predetermined axial location of an inner wall (29, 29') of the channel so as to provide a seal between the inner wall of the channel and the strand, when the strand is in the channel, said seal element comprising an elastic material; wherein the inner wall (29, 29') of the channel comprises an annular or cylindrical recessed region (27, 29'), longitudinally coaxial with the channel, for accommodating the seal element so as to retain the seal element at the predetermined axial location during an axial displacement of the strand in the channel, the sealing element being removably arranged in the recessed region (27, 29'), the cable anchorage being characterised in that: the seal element and the second channel end of the channel are formed such that the seal element can be introduced into the channel through the second channel end, the seal element and the inner wall (29, 29') of the channel are designed such that the seal element is axially displaceable inside the channel from the second channel end to the predetermined axial location, the seal element is elastically deformable to a compressed state, in which it has a radial outer dimension which is smaller than or equal to all diameters of the inner wall of the channel between said second channel end and said seal element, and the ratio of the axial length of the recess to the axial length of the sealing element is greater than 1.1 but less than 1.5. the seal element and the second channel end of the channel are formed such that the seal element can be introduced into the channel through the second channel end, the seal element and the inner wall (29, 29') of the channel are designed such that the seal element is axially displaceable inside the channel from the second channel end to the predetermined axial location, the seal element is elastically deformable to a compressed state, in which it has a radial outer dimension which is smaller than or equal to all diameters of the inner wall of the channel between said second channel end and said seal element, and the ratio of the axial length of the recess to the axial length of the sealing element is greater than 1.1 but less than 1.5.