If you are not a US citizen you have fewer rights if you are arrested in the US. Even fewer if it's via extraordinary rendition.
Incidentally, the rights of the accused are stronger in the US than in any other jurisdiction in the world. He has the unqualified right to remain silent and to a jury trial in which illegally gathered evidence is excluded. He would have neither of those in the UK.
1: http://www.cps.gov.uk/legal/a_to_c/confession_and_breaches_o... 2: https://en.wikipedia.org/wiki/Right_to_silence_in_England_an... 3: http://www.bailii.org/eu/cases/ECHR/1996/3.html#para45
In the UK, police can use your silence at time of questioning to cast doubt on future exculpatory claims that you make. In the US, the government can never make that argument in court. So in the US, the best course of action is, without qualification, to remain silent until speaking to a lawyer. In the UK, doing that can be presented as evidence of your guilt. https://en.wikipedia.org/wiki/Right_to_silence_in_England_an...
The United States is the only country to take the position that some police misconduct must automatically result in the suppression of physical evidence. The rule applies whether the misconduct is slight or serious, and without regard to the gravity of the crime or the power of the evidence. “Foreign countries have flatly rejected our approach,” said Craig M. Bradley, an expert in comparative criminal law at Indiana University. “In every other country, it’s up to the trial judge to decide whether police misconduct has risen to the level of requiring the exclusion of evidence.” https://mobile.nytimes.com/2008/07/19/us/19exclude.html
On the flip side, UK police are far more constrained in their actions when interviewing suspects than US police are:
@ UK police are not permitted to lie to suspects in interviews
@ Interviews must be recorded from start to finish.
@ No abusive use of plea bargains: we don’t do the “take this plea bargain or risk being locked up for 60 years” thing at all.
I’m sure there are more, but those are the things that spring to mind immediately.
I’m not going to pretend that everything in the UK is sweetness and light regarding our police, but the idea that the US is a haven of civil rights compared to the UK is just completely wrong-headed.
There are further differences. For instance:
* Like most of Europe, the UK doesn't have an exclusionary rule for illegitimately obtained evidence. Unauthorized searches can produce evidence admissible in court.
* Defendants in the UK don't have the same right to avoid self-incrimination that US defendants do.
* Evidence obtained through entrapment can be admissible in UK courts.
* There's precedent in the UK for secret criminal trials (the US has "secret courts", but those courts have no powers to hear criminal cases).
* The UK accused can be held for up to 28 days without charge.
* Terror suspects in the UK can be placed on what is effectively house arrest indefinitely, without criminal charges.
If you discount parallel construction
Non-US citizens arrested in the US will potentially face deportation and permanent expulsion if the crimes are serious enough, like rape or murder. Other than that the police will likely treat you just the same as any American, which is not necessarily great but at least it's equitable.
Now the federal law enforcement departments are more brutal in their techniques. They're usually only involved in serious crimes though.
And extraordinary renditions are illegal kidnappings so I don't think there's any expectation of rights afforded or decency shown in that sort of situation. You're gonna get tortured in Egypt/etc. whether you're an American or not.
Any felony is grounds for deportation and permanent expulsion regardless of how "serious" it might be.