The 1951 Presidential Address included reference to 275-kV developments on the British Grid system and the paper forms an interim report of progress made by the British Electricity Authority on this project. Part 1 sets out briefly the basic investigations carried out which established the technical necessity and economic justification for the new system, the main outlines of the scheme proposed and the operating voltage. Part 2 deals with some of the research on losses and radio interference at high voltage, which, following earlier work, have had a significant bearing on the selection of the size of conductors and insulation characteristics. Part 3 describes the progress made in settling specific design and performance characteristics which have been incorporated in detailed specifications. Contracts have been placed with British manufacturers for substantial sections of this scheme, the first stage of which is due to be in commission by 1955.