A method of continuously forming heated conduit (17) includes performing a tape (31) for winding onto a spiral pipeline former. At least one conductor (4,5) is positioned adjacent to the centreline of and parallel with a thin polymer ribbon. The ribbon is folded in half to encapsulate the conductors. The folded ribbon is thermally welded to itself. The folded, welded, ribbon is passed through a creaser, which forms a crease midway across the folded ribbon. The creased pre-formed ribbon is formed into a conduit in a continuous process on a spiral pipeline former (24).
