no, No, NO! I'm totally pro-privacy. And in fact, if AT&T wanted to sell the content of my conversation (i.e. what I'm talking about), then I would be just as upset. But they aren't and neither is the UK. (Again: assuming you believe the gov't).
Look: Another analogy is a letter sent through the mail. If you want to keep your mail correspondence private, you need to make sure that you don't write anything incriminating on the outside of the envelope. You can expect that the stuff INSIDE the envelope
is private, but since the destination address must be visible in order to deliver the letter, you cannot expect that the destination address will be private. In fact, you can avoid the source address if you wish because it is a one-way conversation.
In order for a phone connection to work, you need the source and destination because you actually set up 2 connections, not 1. One connection goes from source to dest and the other goes from dest to source. Because the source and destation (i.e. the phone
numbers) are thrown all over the network, you have no reasonable expectation of privacy for that information.
The expectation of privacy (which isn't a right, btw, the constitution says illegal search and siezure, not privacy, but whatever) extends to purposefully private areas. It does not preclude what people can plainly see nor does it preclude what you make no
attempt to hide.
When you call someone on the phone, you start off by having a conversation between you and the phone company wherein you tell them what number you are and what number you want to dial. Once they complete the connection, your conversation with the phone company
ends and now you are talking to the person at the other end.