An umbilical for use in the offshore production of hydrocarbons, the umbilical comprising at least one electric cable, the electric cable comprising at least one electric conductor (18), and at least one electric conductor (18) comprising plurality of electric strands having interstices (15), wherein the interstices are filled with a metal-based material. In this way, there is provided an umbilical with a ‘void-free1 or completely gap-filled conductor construction which therefore prevents water or gas migration or transport along such a conductor.