Abstract: A superconducting lead comprises a supporting board (1) with at least one superconducting tape (3) adhered to it and extending from one terminal area of the lead to another. Respective metal end-fittings soldered to the superconducting tape (3) at each of its ends, and in each of the terminal areas at least one metal insert is bonded to the board (1) and also soldered to the corresponding one of the said end-fittings, so relieving the tapes (3) of mechanical stress. The board (1), or each of them, is preferably flat and may support two or more superconducting tapes (3) coplanar with one another on one or on each of its major faces. The metal inserts are preferably of copper and may be made by removing most of the copper cladding from a commercially available circuit board (1).