I do believe that the BBC Trust model has much to be said for it. But in the end, it's not my job to defend the model but to make it work effectively on behalf of the public.
If others wish to debate the pros and cons of different structures, then so be it.
But I would just raise some cautionary thoughts. The BBC has always had its critics. I doubt if there has been a single moment in its long existence when there has not been a lengthy queue of experts pressing for change to this or that aspect of its activities and structure.
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And this is how it should be. The degree of public scrutiny the BBC attracts is a confirmation of the centrality of the BBC to the social, economic and cultural life of Britain. But there are two kinds of critics of the BBC and of its governance arrangements.
There are those who have the best interests of the public at heart and who genuinely want to see change to ensure the BBC serves the public better. And there are those who put private interests first – and who see the BBC as an obstacle to the furtherance of those private interests, whether they be commercial, or political, and who seek to further those interests by weakening the BBC.
I think the public very well understands the difference between the two kinds of critics.
I repeat that the current Charter runs until 2016 for a very good reason – it underpins the BBC's independence. But when the time comes for a debate over the governance arrangements for the BBC, then there are two tests the public will want to apply to any fresh proposals.
The first is: do they secure a strong challenge to BBC management on behalf of the public interest? And the second is: do they also protect the independence of the BBC from undue commercial or political influence? In applying these tests, the public will want to scrutinise not just the proposals themselves but also the motives that lie beneath them.
And the public will rightly be suspicious about those seeking commercial advantage and those pressing for stronger political control – however it is disguised.