Polymeric articles

A process for the production of a hollow heat-recoverable article provided with a functional insert which comprises deforming a substantially non-crosslinked polymeric material at a temperature below the crystalline melting point or softening point of the material to render the material heat-recoverable, disposing said functional insert in contact with an exposed portion of said material, fusing together parts of the deformed material or a part or parts of the material and at least one other polymeric component to produce at least one hollow heat-recoverable article with the functional insert located therein and subsequently cross-linking the substantially non-cross-linked polymeric material.