honey I'm not an international-law expert (LOL) but it's clear to me the UK and China signed an agreement related to then-UK territory, so the UK now wants China to adhere to that agreement, and in that sense 'the UK represents Hong Kong's interests' (until 2047)
as I said, I'm not a lawyer, so it'd be easy to defeat me in a play of words now; go ahead if you want
The declaration was signed on 1984 and was a declaration on return of Hong Kong to China on July 1, 1997. Hence there was intentionally no declaration of UK actions post 1997 handover. This is done and now history,
GEEZ Do people don't know how to read anymore or just being coy.
"The Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the People's Republic of China have reviewed with satisfaction the friendly relations existing between the two Governments and peoples in recent years and a
greed that a proper negotiated settlement of the question of Hong Kong, which is left over from the past, is conducive to the maintenance of the prosperity and stability of Hong Kong and to the further strengthening and development of the relations between the two countries on a new basis. To this end, they have, after talks between the delegations of the two Governments, agreed to declare as follows:
1.
The Government of the People's Republic of China declares that to recover the Hong Kong area (including Hong Kong Island, Kowloon and the New Territories, hereinafter referred to as Hong Kong) is the common aspiration of the entire Chinese people, and that it has
decided to resume the exercise of sovereignty over Hong Kong with effect from 1 July 1997."