Hong Kong yesterday finally acquired a formal administrative frontier - 12 days before it is handed back to China.
The border, one of the world's busiest, is expected to remain the boundary when China makes the map of the Special Administrative Region.
Deputy political adviser John Ashton yesterday headed a Hong Kong government delegation to sign a memorandum of understanding with Guangdong officials in Shenzhen.
It is the product of 14 rounds of talks over the past nine years.
A draft agreement on the boundary was reached in January, followed by a joint survey to define the territorial waters and land boundary.
The memorandum was formally signed yesterday and took effect immediately after the ceremony.
No one who now lives in Hong Kong will find themselves living in Guangdong.
