http://www.bbc.co.uk/news/uk-23495314
Apparently, the most common reason for refusing to repatriate is because the Human Rights Act prevents us releasing them to their native countries.
Clearly, I'm torn between pride in the rigour of the legal system, and horror that the HRA is directly denying justice to the people most affected by the crimes.
As a meta-issue, I am increasingly concerned that international treaties of every stripe are a threat to national sovereignty and democracy.