[em500]

Not easy at all, good luck getting it accepted by both the UK parliament and by Deng Xiaoping. People have this notion that the UK could do whatever they wanted in HK before 1997 (or at least before the negotiations with the PRC in the 1980s). But recently declassified documents revealed that the PRC was already pressuring the UK about HK affairs back in the 1950s.

[NeedMoreTea]

They weakened status well before the joint agreement. Yet right after Tiananmen Square, and after the joint agreement, they managed to rapidly dream up a selection of 50k families, so they were also far from powerless to act without Deng Xiaoping's approval. Thousands of HKers were leaving after Tiananmen, to anywhere that would take them, so it's not like it would have deprived China of those citizens after 97 handover.

[em500]

There's a big difference between accepting 50k and 5million people, on both the British and the Chinese side.

[frosted-flakes]

50k families is more like 200k–300k people.