SP your concern is spurious.
Every time you (or any bank customer) issues a cheque it contains your sort code and account number on it. This is not information that is (or needs to be kept) secure.
I sigh deeply every time individuals such as Gromit or organisations like Liberty attempt to wind people up over this.
Point 1: you can't stop organisations eavesdropping onto communications signals. Wireless is out there for anyone with big enough ears. Cables have been tapped into since Victorian times (undersea telex cables, for example).
Point 2 : (virtually) all systems of encryption can be broken given enough time. That's the point - the time it takes, even for those with huge budgets and virtually infinite storage capability. Think cracking Enigma, then scale up millions of times over.
Point 3 : Having broken it, you then seek to see if any content appears relevant by a matching technique - does it contain key matched data of potential source of interest. If so, you go back trawling for similar data from the same source, unencrypt that and look there too. There aren't armies of people listening with headphones, whatever. Its about data matching. Tiny needles within in massive haystacks. And at best you are sometimes guessing what the 'needle' you are searching for actually looks like.
Point 4 : You have to do all of this quickly before your interim storage of the world's data transmissions made in the last x days runs out, when you write over the data with more recent transmissions. Old data is then lost forever. Time is important.
Snoopers charter? Pah, get real. I'm more interested in keeping tabs on individuals interested in causing harm.