A method of manufacturing a pipeline for subsea transportation of oil and gas, the method comprising the steps of: (a) providing a metallic pipe having an external surface, optionally having an intermediate layer formed on the external surface, the metallic pipe having a plurality of electrical cables (15A, 15B, 15C, 15D) located on its external surface or on the intermediate layer when present, (b) applying a first coating of a thermoset material to a section of the metallic pipe to form a coated section of the metallic pipe, and (c) applying a first coating of a thermoset material to a further section of the metallic pipe, wherein the coating is applied such that it overlaps with or abuts the previously coated section of the metallic pipe, wherein the plurality of electrical cables (15A, 15B, 15C, 15D) are wound helically around the external surface of the metallic pipe or the intermediate layer when present, wherein step (b) comprises providing a mould for applying the thermoset material, closing the mould around the section of metallic pipe to be coated, and injecting the thermoset material into the mould to coat the section of metallic pipe with the thermoset material, wherein, when the mould is closed around the section of metallic pipe to be coated, the mould comprises first and second open ends which surround the metallic pipe, and substantial sealing of the open ends (35B, 35A) is provided at a first end by a section of metallic pipe to which the thermoset coating has already been applied and at a second end by a sealing ring placed around the metallic pipe, and wherein the sealing ring has an internal, metallic pipe facing, surface in which are formed grooves (80A, 80B, 80C, 80D) which are shaped to accept the plurality of electrical cables 15A, 15B, 15C, 15D) on the external surface of the metallic pipe or on the intermediate layer when present. (a) providing a metallic pipe having an external surface, optionally having an intermediate layer formed on the external surface, the metallic pipe having a plurality of electrical cables (15A, 15B, 15C, 15D) located on its external surface or on the intermediate layer when present, (b) applying a first coating of a thermoset material to a section of the metallic pipe to form a coated section of the metallic pipe, and (c) applying a first coating of a thermoset material to a further section of the metallic pipe, wherein the coating is applied such that it overlaps with or abuts the previously coated section of the metallic pipe, wherein the plurality of electrical cables (15A, 15B, 15C, 15D) are wound helically around the external surface of the metallic pipe or the intermediate layer when present, wherein step (b) comprises providing a mould for applying the thermoset material, closing the mould around the section of metallic pipe to be coated, and injecting the thermoset material into the mould to coat the section of metallic pipe with the thermoset material, wherein, when the mould is closed around the section of metallic pipe to be coated, the mould comprises first and second open ends which surround the metallic pipe, and substantial sealing of the open ends (35B, 35A) is provided at a first end by a section of metallic pipe to which the thermoset coating has already been applied and at a second end by a sealing ring placed around the metallic pipe, and wherein the sealing ring has an internal, metallic pipe facing, surface in which are formed grooves (80A, 80B, 80C, 80D) which are shaped to accept the plurality of electrical cables 15A, 15B, 15C, 15D) on the external surface of the metallic pipe or on the intermediate layer when present.