Monitoring the pipes is also pretty greasy, but people consider those 'public' anyway and encrypt if necessary.
Also, the UK Regulation of Investigatory Powers Act (RIPA) which is the main law governing spies doing mass collection of content and meta-data has many more abuses - (http://www.telegraph.co.uk/news/uknews/2696031/Anti-terroris...)
> An investigation by The Sunday Telegraph found that three quarters of local authorities have used the Regulation of Investigatory Powers Act (RIPA) 2000 over the past year. The Act gives councils the right to place residents and businesses under surveillance, trace telephone and email accounts and even send staff on undercover missions.
These are all active, ongoing, abuses against real people using real data. It is a problem that GCHQ collects data, and it's a problem even if they don't grep it because eg McCarthyism could happen.
The UKCrypto mailling list possibly has some discussion about the UK laws and the requirement to not let anyone know if you're being investigated. But I have no idea what to search for. (http://www.chiark.greenend.org.uk/pipermail/ukcrypto/)