Hong Kong itself as well as the Kowloon peninsula were actual territories that belonged to the UK after they were ceded to them after the opium wars.
It’s only the “new teritories” which were several smaller islands surrounding Hong Kong island that were part of the 99 year lease.
Even if no effort was made to secure the new territories, we could have and should have defended Hong Kong and Kowloon as part of Britiain, as the people wanted to be either independent or remain British.
Thatcher rolled over and sold their futures to appease China.
A hotel room being "full doesn’t necessarily mean the guest is in the room at that very moment, just that the room us reserved. And given infinite rooms it’s basically guaranteed one of those reservations is for sisyphus