The composition of BBC audiences

People have long wondered how BBC audiences always seem more left-wing and politically correct than one would expect. Biased-BBC has been pondering this for some time and Beeb Bias Craig did as well. Peter Whittle in Standpoint muses on this point and makes a good point:

'Take immigration: a number one concern as measured by poll after poll. The strength of feeling on this issue is never reflected in public audiences, whether they be for Question Time, Any Questions or indeed The Big Questions. Instead, the most that happens is that public feeling is referred to, often by the host, as being strong. The audiences themselves always seem much more ambivalent.'

But then gives the BBC too much credit:

'I'm not sure how audiences are selected by the broadcasters. And I'm certainly not claiming that there's any kind of conspiracy. Rather I imagine that a fair system is used which, oddly, goes on to produce an unfair, unrealistic result. To maintain 'impartiality', production teams might strive for 50% pro, 50% con on any given issue. The impression one is left with is that there is much more argument and disagreement than there actually is.'

I disagree, I believe that BBC current affairs audiences are unrepresentative of public opinion and the BBC know and approve.