> If the treaty is UK law, they can take the case to UK courts. It's not guaranteed to work, it depends on the legal technicalities, but the government has no say in the findings of UK courts.

Presently, the UK lacks an entrenched written constitution. Hence, any court decision can be overturned by an ordinary Act of the UK Parliament, passed by a simple majority. If a court makes a ruling which the government of the day sufficiently dislikes, the court ruling will be overturned, assuming the government has the numbers to get the legislation through the House of Commons and House of Lords.

But, in 99 years time, who knows. Maybe by then, the UK will have a written constitution. Maybe by then, the UK won't even exist anymore. Maybe by the time the lease expires, it will actually be between Mauritius and the English Republic.

until the government decides that only evidence they like can be presented to the court like the last administration did with their Rwanda plan for migrants.

The UK government never wanted to keep Hong Kong. (It may have wanted to pantomime trying to keep it to placate some voters).

While the UK did have a long history of legal continuity, it's made a lot of dramatic changes in recent years - the switch to the Supreme Court which has then made some legally bizarre decisions, the complete demolition of the House of Lords over a pretty short period, the efforts to entrench human rights legislation which have simply no precedent in UK constitutional history at all...

as always UK courts favour their country/people.

Well someone more powerful would not care about the lease agreements anyway so if the U.S can’t fight back the lease agreement won’t help them anyway. See Russia-Ukcraine and the agreements that were signed. They are not worth their paper