Bagehot's blog on the Economist web site has a defense of the BBC which includes this observation:

Yes, it is a clique-ish institution, and snobbish towards outsiders. I have bumped into BBC teams on four continents, at airports or election rallies or hotel lobbies late at night after some long story, and have routinely marvelled at their incestuous, clannish manner. In terms of insiderishness, I think only a travelling hockey team from a very grand girls' boarding school comes close.