Power of US
Simple - he should be tried under in the UK under UK law, that’s where the offence was committed.
The limited information, that is in the public domain, indicates that US are more embarrassed than hurt and want to make an example of someone.
If the guy is in the US he has no hope of a fair trial as the US have already pronounced him guilty. He may have been stupid but something like 90 years in jail is stupider!
UK Law should remain above that approach. If I have never been in the US then why should that government try to impose its law on me?
I hope the Law Lords maintain the level of resistance that they have for many years held against political intervention.