[Kojak]

You’d be surprised at how many people watch both bulletins. (Same goes for the 6.30 and 10 on ITV). It would thus make sense for the two bulletins to have at least slightly different agendas.

Plus, even for people who aren't watching both, having slightly different focuses - typically domestic social affairs for the Six and politics and international news for the Ten - adds a selling point to the respective bulletins.

Also, on the point of different agendas, I recall that one of the British Election Studies (87 or 92) asked about people's perception of ideological leanings of various newspapers and TV/radio programmes - including the BBC's Six and Nine O'Clock Newses - and there were a small but not insignificant number of respondents who thought that one BBC bulletin was biased towards one party and the other leant in the opposite direction! How much of that was genuine feeling and how much was 'not bothered, random answer' was difficult to work out.

I think the way ITV’s 6.30 and 10pm bulletins are different illustrates this point perfectly. 6.30 is (much like the Six) geared more towards home social affairs and, to a lesser extent, human interest/‘news you can use’. News at Ten, meanwhile, is based much more around politics, international news and analysis. I see it as no coincidence that the ratings of the latter have increased since it adopted its current format and stopped being a repeat of the 6.30 news. (Criticisms of Tom Bradby aside…)