In 1964, driven by the need to compete more effectively in world markets, Thorn merged its lighting interests with those of Associated Electrical Industries (AEI) to form British Lighting Industries Ltd, taking a controlling 65% share (the remaining 35% being acquired three years later). AEI Lamp and Lighting brought to the BLI group three significant lighting interests: The British Thompson-Houston Co Ltd (BTH) which owned major factories, especially at Leicester in the East Midlands of England (producing discharge lamps) and in Hereford, near the Welsh border (making luminaires), and sold lamps under the ‘Mazda’ brand; the Metropolitan-Vickers Electric Co Ltd (MV) which drew supplies from the BTH factories, selling them under the 'Metrovick' brand; and the Edison Swan Electric Co. Ltd (Ediswan), which had recently transferred its factory at Ponders End and ‘Royal Ediswan’ brand over to BTH.