A good article from The Guardian on what happens when you get arrested for being a terrorist suspect in the UK. Note the following logic the police used to figure out he was a suspected terrorist!!

They handcuff me, hands behind my back, and take my rucksack out of my sight. They explain that this is for my safety, and that they are acting under the authority of the Terrorism Act. I am told that I am being stopped and searched because:

- they found my behaviour suspicious from direct observation and then from watching me on the CCTV system;

- I went into the station without looking at the police officers at the entrance or by the gates;

- two other men entered the station at about the same time as me;

- I am wearing a jacket “too warm for the season”;

- I am carrying a bulky rucksack, and kept my rucksack with me at all times;

- I looked at people coming on the platform;

- I played with my phone and then took a paper from inside my jacket.

Particularly relevant in light of attempts here to introduce laws which would allow people to be detained without legal representation, or even being informed what they are being detained for.