[buckminster]

Extradition requires dual criminality. If you can extradite you can prosecute the offence locally.

[detaro]

I don't think that's universally true? E.g. reading the judgement here, when evaluating the charges regarding the conspiracy to obtain national security documents, does not ask "is stealing US national security documents against UK law", but rather "if Manning had been a UK army member, targeting the UK, would this have been against UK law", finding that would be the case and thus accepting the conspiracy charges as fulfilling dual criminality.

But you couldn't prosecute Assange in the UK for conspiracy to steal documents from the US and damage done to US national security, but at best for damage done to UK national security through that.

(It's possible I am misunderstanding something?)