<P> Top of the Pops was created by BBC producer Johnnie Stewart, inspired by the popular Teen and Twenty Disc Club which aired on Radio Luxembourg . It was first aired in 1964 and was originally based on the Top 20 . By 1970 the Top 30 was being used and the show was extended from 30 to 45 minutes duration . The show was also now shown in colour following the BBC1 upgrade in November 1969 . A switch to the Top 40 was made in 1984 . (Radio One also changed to the Top 30 in the early 70s and to the Top 40 in 1978). </P> <P> The show saw many changes through the decades, in style, design, fashion and taste . It periodically had some aspect of its title sequence, logo and theme tune, format, or set design altered in some way, keeping the show looking modern despite its age . The programme had several executive producers during its run (although not all were billed as such), in charge of the overall production of the show, although specific content on individual shows was sometimes decided by other producers . When Stewart left the show in 1973, after nearly 10 years in charge, he was replaced by Robin Nash . Both Stewart and Nash made brief returns to the show as producer after they left, in 1976 and 1981 respectively . </P> <P> Stewart devised the rules which governed how the show would operate: the programme would always end with the number one record, which was the only record that could appear in consecutive weeks . The show would include the highest new entry and (if not featured in the previous week) the highest climber on the charts, and omit any song going down in the chart . Tracks could be featured in consecutive weeks in different formats . For example, if a song was played over the chart countdown or the closing credits, then it was acceptable for the act to appear in the studio the following week . </P> <P> These rules were sometimes interpreted flexibly and were more formally relaxed from 1997 when records descending the charts were featured more regularly, possibly as a response to the changing nature of the Top 40 (in the late 1990s and early 2000s climbers in the charts were a rarity, with almost all singles peaking at their debut position). </P>

What was the theme tune to top of the pops