Britain is simply an island.
Can you be specific about which legal cases you are in outrage over?
If you are talking about David Miranda then he was lucky that we treated him so leniently.
As a former military intelligence operator I wrote a piece on the detention: http://urbantimes.co/2013/11/the-david-miranda-detention-why...
We were exceptionally lenient and reasonable in our treatment of David Miranda, regardless of what the general populace think.
He was a foreign national, in possession of UK Top Secret documentation, held on a non-secure IT system, and he was not a journalist. Why would anybody in their right mind think we would allow a foreign national to waltz off with our material is beyond me.
Replace "David Miranda" with "Chinese Hacker" or "North Korean Diplomat" and ask whether the detention would have been lawful then.
“A Chinese computer hacker was arrested with 58,000 TOP SECRET files from the UK intelligence community. He was spoken to for 9 hours and released without charge. He is requesting the return of his computer.” The UK public would be up in arms if our police services released that individual back to his host nation.
You think you get a free pass for being the partner of Glenn Greenwald?