colour of balls is important) did not reach the heights of its popularity until the 1980s. Notable dramas included Play for Today and Pennies from Heaven. In police dramas, there was a move towards increasing realism; popular shows included Dixon of Dock Green, Z-Cars, Softly, Softly, and The Sweeney. The science fiction show Doctor Who reached its peak. 1970s UK television featured a mix of traditional and more modern comedy. Morecambe and Wise, The Benny Hill Show, Are You Being Served? and Dad's Army had their origins in the variety show and radio comedy of the first half of the century. Many popular British situation comedies (sit-coms) were gentle, unchallenging comedies of middle-class life; typical examples were Terry and June and Sykes. However, the middle-class settings of The Good Life and The Fall and Rise of Reginald Perrin contrasted with their anti-establishment theme of people rejecting traditional social norms. A harsher side of society was shown by comedy series like Porridge and Rising Damp, while sitcoms such as Mind Your Language, Love Thy Neighbour and Till Death Us Do Part reflected social unease brought about by post-war immigration. Spike Milligan's Q and the still-popular Monty Python's Flying Circus both used surreal comedy, originating from the 1950s The Goon Show. The television information retrieval service Teletext was initially introduced when the BBC Ceefax system went live on 23 September 1974. In the late 1970s, BBC2's unveiled a new identity, a twin-striped "2", which was the first electronically generated symbol and scrolled on and off the screen. United States As the 1970s began, the Big Three TV networks were rapidly re-engineering their lineups, noting that existing programs were not attracting the youth audience. Most existing programs still operated on paradigms established in the 1950s, and some shows had literally been on the air since the dawn of TV broadcasting in the late 1940s and early 1950s. Shows that had low ratings or insufficient youth appeal were cancelled as networks scrambled to attract the large baby boomer audience. To reflect the new social trends, television changed dramatically with more urban and edgy settings, and replaced the popular rural/country wholesome look of the 1950s and 1960s, seen as outmoded and unable to connect with young, educated urban audiences. This particular trend was known as the rural purge. Television was transformed by what became termed as "social consciousness" programming, such as All in the Family