Chinese Government believe that under Chinese Law he would have a defence.
No defence under English Law. Convicted. Recieves life sentence.
Chinese Govt asks UK Government to pardon Chinese convict.
UK Govt refuses - 'no one interferes in British Justice'.
The death penalty is prohibited by the European Convention on Human Rights -but I don't think we ever persuaded China to sign that or any other international instrument banning the death penalty.
Isn't that what we should be doing - persuading them to enter into a international human rights obligation rather than interfering in the domestic legal system of a fellow sovereign state?