Comment by seanhunter

That is not true. The specific powers of arrest and detention by UK border force were set out in this freedom of information response here https://www.whatdotheyknow.com/request/uk_border_force_power...

Summary is they can’t detain people for no reason, they can detain people for specific offences relating to immigration and citizenship, customs and excise and also the normal stuff any regular police officer can arrest people for.

I’m no apologist for how much state authority they have, but it’s not as bad as you’re making out.