The Electricity Commissioners were a department of the United Kingdom government's Ministry of Transport, which regulated the electricity supply industry from 1920 until nationalisation in 1948. It was responsible for securing reorganisation on a regional basis and considered schemes for centralisation in a small number of large generating stations owned by joint electricity authorities. History In 1917, the UK government was planning the reconstruction of the nation's industries after the First World War. The Board of Trade set up the Electric Power Supply Committee, chaired by Sir Archibald Williamson, which proposed the effective nationalisation of the industry. Subsequently, in 1919 under the chairmanship of Sir Henry Birchenough, the Advisory Council to the Ministry of Reconstruction produced the Report of the Committee of Chairmen on Electric Power Supply. The committee were asked to submit general comments or suggestions on the broad administrative and commercial issues which had arisen out of the Williamson Report. The Birchenough Committee generally agreed with the Williamson Report but recommended that generation and transmission should be a single unified system with state regulation and finance and that means should be found for including distribution as well. This recommendation was very far-sighted but considered too ambitious by the government. If acted upon it would have anticipated the Electricity Act 1947 by 28 years. Parliament rejected what would have been the effective nationalisation of the industry but enacted two of the committee's recommendations in a weaker form, including the setting up Electricity Commissioners and a number of joint electricity authorities formed by the electricity suppliers in each area. The Electricity (Supply) Act 1919, was based essentially on the Williamson and Birchenough reports and introduced central co-ordination by establishing the Electricity Commissioners, an official body responsible for securing reorganisation on a regional basis. Operations In 1925 the commissioners approved a system for the standardisation of electricity supply. The generation and distribution of electricity was undertaken at a range of voltages and frequencies; 109 suppliers provided AC only, 297 DC only, and 176 both AC and DC. Supply voltages ranged from 100 V to >3,000 V. AC was supplied at 15 different frequencies ranging from 25 Hz to 100 Hz, even at the most common frequency of 50 Hz (supplied by 223 undertakings) some provided single phase, some two-phase and some three-phase. The standard proposed by the commissioners was three-phase AC of 6.6 kV (or 11 kV, 33 kV, 49.5 kV