In 1997 I stood in driving monsoonal rain on the border of Hong Kong and the China mainland and watched the Peoples Liberation Army in trucks and armoured personnel carriers pour in to reclaim the territory. Not even a decade earlier that army had massacred its own people in Tiananmen Square, in another decade China would host the Olympic Games.

I was in no doubt the world was turning. Reclaiming Hong Kong marked the return of China as a great power. For Beijing it was a repudiation of what the Chinese call the hundred years of humiliation beginning with the 19th century Opium Wars when Britain seized control of Hong Kong and later ritually torched the Summer Palace in Beijing.

Chinese troops enter at the Luk Ma Chau border between China and Hong Kong in the New Territories to take up positions in China's newly reclaimed territory in July 1997. Credit:AP

It is seared into Chinese memory. The humiliation ended with the communist revolution and the birth of the People’s Republic of China in 1949. In tense negotiations with Britain over Hong Kong’s future in the 1980s, China’s leader Deng Xiaoping warned Margaret Thatcher that he could march his army in and take the territory back in a day if he wanted to.

But even then Thatcher still believed Deng and his comrades were on borrowed time, their political system she said "was false in the long term". The Chinese, she believed "had little understanding of the legal and political conditions of capitalism".