In the 15 years since Hong Kong returned to China, its residents have developed an increasing sense of "one country". However, chief executive-elect Leung Chun-ying said it will take a long time before remnants of colonial influence disappear entirely.

International military bands line up during a rehearsal for the International Military Tattoo in Hong Kong on Thursday. The tattoo was held from Friday to Sunday in celebration of the 15th anniversary of the establishment of the Hong Kong Special Administrative Region. Antony Dickson / Agence France-Presse

Since the handover in 1997, about 300,000 Hong Kong residents have gone to work on the mainland, Leung said, citing incomplete statistics. "It is a considerable number, given the total working population in Hong Kong is 3.7 million," he said.

However, many small things in daily life show that the influence of colonial governance can still be seen in the special administrative region.

For example, instead of saying "going to the mainland", some Hong Kong people still say they are "leaving for China", he said. He also quoted a mainland friend quoting a Hong Kong saleswoman who said she once visited Beijing on "your National Day".

"They may not have any special political stance, but Hong Kong was under British colonial control for more than 100 years, and it's not easy to remove the influence on people's feelings instantly," he said. "We'll keep doing our job on this, but we cannot rush. It should be done step by step."

Leung said the work requires education about history to make Hong Kong people better understand the country, as well as work to bring people from Hong Kong and the mainland closer.

First, he said, to draw people's feeling closer to the motherland, efforts must be made first to unite Hong Kong people.

Leung, whose father left Weihai in Shandong province to work as a policeman in Hong Kong 80 years ago, said many people, including his parents, regarded Hong Kong as only a temporary stop in their journey.

His parents' generation always wanted to return to the mainland, but many Hong Kong people in the 1970s and 1980s migrated to other countries.

"It is a very important job to have the 7 million Hong Kong people regard Hong Kong as their home," he said.