changes in contractors, as the huge cost in switching to colour television would have made the companies unable to compete against rivals in a franchise battle. It also allowed the companies to recoup the cost and to return to normal service. Some slight changes were made to the Yorkshire Television franchise area however, as the Belmont transmitter in Lincolnshire switched from Anglia Television to Yorkshire Television, boosting the broadcast area. Launch of Oracle teletext This period also saw the launch of the Oracle teletext service. It was officially launched in 1978, a few years after the launch of the BBC's Ceefax service and offered news and information delivered through the remaining lines of information in the television transmission. The service began to see improved takings following a heavy promotional campaign using the slogan Page the Oracle and the inclusion of the software as standard in most new television sets at the beginning of the 1980s. 1979 dispute ITV suffered an eleven-week industrial dispute in 1979, leading to the subsequent shutdown of almost all ITV broadcasts and productions. It began at London's Thames Television when electricians, who were EETPU members, refused to accept what they considered to be a derisory pay increase. The management attempted to operate a normal service, but other transmission staff, who were ACTT members, refused to co-operate, pointing out that equipment and wiring turned on by non-EETPU members could be potentially dangerous. Thames management interpreted this as a walkout. When Thames' management consequently ordered the striking staff to "return or else", the broadcasting union, the ACTT, instructed members at thirteen other ITV stations to walk out in solidarity. The only company unaffected was Channel Television, as the unions recognised that industrial action there could lead to the station's closure, as its small audience made it vulnerable to any loss of advertising revenue. ITV viewers encountered blank television screens on the morning of 10 August 1979, and were left without any programmes. Later on, an apology caption would broadcast in 14 of the 15 ITV regions. Strangely, the caption achieved ratings of around one million, from TV sets left on in the hope that the strike would end. Only one ITV company broadcast anything during this time, that being Channel Television, who broadcast a time-restricted service of local programming, films and imported television series (on film, as Channel had no videotape facilities at the time). An example of