Cui said Beijing would continue to seek reunification by peaceful means, and as long as the one-China principle was respected, “everything else is negotiable”.

But he warned of “limits” to how far the country could be provoked on this issue.

During their summit on Wednesday, Xi demanded directly of Biden that Washington stop its arms sales to Taiwan, describing it as “the most dangerous” flashpoint in US-China tensions. In public, Biden would only say the US’ one-China policy remained unchanged.

03:12

Xi Jinping, Joe Biden hold talks on sidelines of Apec summit to ease strained US-China ties

Xi Jinping, Joe Biden hold talks on sidelines of Apec summit to ease strained US-China ties

Cui, who served as Beijing’s ambassador to the US from 2013 to 2021, has since retired but continues to engage actively in non-official China-US exchanges.

“I think that the two countries are still in this, maybe, historic stage, or period, redefining the relations, or finding a correct way of dealing with each other going forward. This is not done yet. We are still in this stage,” he said.

“For such a complex relationship, maybe we need some time to do this … The real strength of this relationship is that sooner or later, the two countries always find ways to overcome the difficulties and move their relations forward.”

“I think Hong Kong still has all its strengths. You have very good economic infrastructure. You have a very developed financial market. You have all the institutions and you are so open. And Hong Kong’s ties with the mainland are a plus for Hong Kong,” he said.

“People should realise this, because you are supported, you are part of the Greater China market, a growing market, and I don’t think very many other economies have this kind of a special advantage.”

Cui’s optimism about Hong Kong, which he described as one of the safest and most prosperous cities in the world, goes back many years.

He has long been a close friend of its first chief executive, Tung Chee-hwa, and a respected voice in explaining to American audiences the “one country, two systems” policy under which the city is governed.

He also lashed out at Washington’s “abuse” of the national security narrative to curb China’s economic rise, urging the US to remove trade barriers hampering mutual business interests.

On China’s relationship with the wider world beyond the US, the veteran diplomat expressed confidence in the so-called Global South as a force for change and peace to counter the dominant Western narrative.

04:15

How the mighty US is a bully on the back of little Hong Kong

How the mighty US is a bully on the back of little Hong Kong

Cui blamed tensions over the South China Sea on the US, saying Washington’s military presence in the region was making it more difficult for China to resolve its territorial disputes with Asian neighbours.

He noted that China had “always” been a strong advocate for peace during times of serious conflict ranging from the Balkan and Iraq wars to today’s crises in Ukraine and Gaza.

“If we talk about the choice between peace and war … we clearly choose the side of peace,” he said.

At age 71, Cui is widely seen as being “retired but not tired”, a description he jokingly disputed on Talking Post.

“I think I should enjoy my retirement,” he said.