Telecommunication cable having an elongated element housing at least one transmitting element. The elongated element has a water-soluble polymeric composition of a vinyl alcohol/vinyl acetate copolymer having a saponification degree of about 60% to about 95%; a plasticizer; a hydrolysis stabilizer compound having a chelant group having two hydrogen atoms bonded to two respective heteroatoms selected from nitrogen, oxygen and sulfur. The two hydrogen atoms have a distance between each other of 4.2×10−10 m to 5.8×10−10 m. The stabilizer compound is present in an amount of at least 0.75 mmoles per 100 g of copolymer. The elongated element is in particular a buffer tube housing a plurality of optical fibers. The presence of the stabilizer reduces the increase of the hydrolysis degree of the copolymer upon aging, thus maintaining the desired water blocking properties of the copolymer.