immediately across the United Kingdom, but some regions had to wait a few more years before colour was available: This was primarily due to the cost incurred in purchasing new broadcasting equipment and the subsequent studio upgrade that usually accompanied it. Colour strike The colour strike was an industrial action by technicians at all ITV companies between 13 November 1970 and 8 February 1971 (although some shows made during this period in black and white were having their first transmission as late as December 1971) who, due to a pay dispute with their management refused to make programmes in colour. Post-colour strike Colour was available to nearly 100% of the United Kingdom from 1976, with the Channel Islands being the last region to be converted. This enabled the 405-line system to be phased out between 1982 and 1985. Three-Day Week The British government imposed early close downs of all three television channels (BBC1, BBC2 and ITV) from 17 December 1973 in order to save electricity during the Three-Day Week, following overtime ban by the National Union of Mineworkers between strike action in the power supply industry and effects of the oil crisis. The early close downs forced ITV (including 14 regional companies) to end their broadcasting day at 10.30pm, thus costing the network much of its advertising revenue. The restrictions were lifted temporarily on 24 December 1973 (Christmas Eve) to allow the public to enjoy festive programming. The restrictions recommenced on 7 January 1974, and ended on 8 February to paved its way for the upcoming general election. 1974–1981 Before the 1979 dispute Following the passing of the Sound Broadcasting Act 1972, the ITA was reconstituted as the Independent Broadcasting Authority (IBA) who took on the same role as the ITA but were also were given responsibility of the then-new Independent Local Radio stations. In 1971, the Bilsdale UHF transmitter, based on the border between Yorkshire Television and Tyne Tees Television and much disputed over, was assigned to Tyne Tees Television. To compensate for this, the IBA allowed Yorkshire Television and Tyne Tees Television to consolidate slightly into a new venture: Trident Television. Trident originally managed advertising sales for Tyne Tees Television and Yorkshire Television but was allowed a reverse takeover of both companies; Tyne Tees Television and Yorkshire Television did however retain their own studio bases, management, boards and on-screen identity. The next franchise round in 1974 produced no