The network has been modified several times through franchise reviews that have taken place in 1963, 1967, 1974, 1980 and 1991, during which broadcast regions have changed and service operators have been replaced. Only one service operator has ever been declared bankrupt, WWN in 1963, with all other operators leaving the network as a result of a franchise review. Separate weekend franchises were removed in 1968 (with the exception of London) and over the years more services were added; these included a national breakfast franchise from 1983 onward—operating between 6:00 am and 9:25 am—and a teletext service. The Broadcasting Act 1990 changed the nature of ITV; the then regulator the IBA was replaced with a light-touch regulator, the ITC; companies became able to purchase other ITV regional companies and franchises were now being awarded based upon a highest-bidder auction, with few safeguards in place. This heavily criticised part of the review saw four operators replaced, and the operators facing different annual payments to the Treasury: Central Television, for example, paid only £2000—despite holding a lucrative and large region—because it was unopposed, while Yorkshire Television paid £37.7 million for a region of the same size and status, owing to heavy competition.