Tom Morris has taken matters into his hands and is asking British Library about its patron privacy policy... The conclusions are not favourable.

My opinion on this is pretty simple: it’s evil and needs rethinking. Patron privacy is one of the biggest issues for me. This won’t affect my use of the library (but I will not be requesting certain books from the BL - rather, I’ll be buying anything controversial or reading it at another library), though I will be making my opinion clear to them in the form of a formal letter. I will also try and get hold of this records management policy. Ideally, they should hold borrowing records only as long as is required for the books to be retrieved from the store, then delete them after the books are returned to the counter. Or, perhaps, a system where patrons can submit a form either online or in person asking that their records be wiped clean. Again, like all privacy concerns, this is simply about ensuring that what should remain private does remain private.

I am sure that the 'if-you-have-nothing-to-hide-you have-nothing-to-be-afraid-of' bridage would completely miss the point on this one too...