The South Bank: Public Sector-Private Land

I was standing outside the National Theatre yesterday afternoon, and a few feet away a man with a video camera was filming the theatre. Two security guards came up to him and told him 'You'll have to put your camera away. There's no filming on the South Bank, it's privately owned.' Apparently the 'no filming' rule was South Bank Centre policy.

What I want to know is this: first of all, how MUCH of the South Bank is private property? Second, how on earth is it privately owned when nearly every building is subsidised by the British Government? I'd read about the privatisation of public space in Joel Bakan's excellent book (and film) The Corporation, but I'd thought it was more of a US phenomenon than a UK one-and it hadn't occurred to me that a private corporation would own the land on which sit the National Theatre, BFI, Hayward Gallery, etc.

Now, in keeping with this blog's focus on learning, research, and teaching, I'm putting out a general call to anybody from any discipline who can shed light on this: social geographers, civil engineers, economists, political scientists, theatre researchers, etc. What's the deal with the South Bank being private?