Tens of thousands of people cross the border everyday

The case is being seen as a major test of Hong Kong's commitment to preserving what is left of the territory's natural environment.

This is a battle between two visions of Hong Kong's future.

One emphasis puts its environment first, the other its development and its infrastructure.

Globally threatened species

At the heart of the dispute, Long Valley is one of the last areas of traditionally-irrigated wetland farming in the former British colony.

Its 25 hectares of spinach and watercress crops attract more than 200 species of birds, among them four that are globally threatened.

Campaigners have described its fate as the most significant environmental decision ever taken in Hong Kong.

The Kowloon Canton Railway Company wants to spend $1bn building a railway through the valley, which it says is needed to carry the increasing number of people travelling between Hong Kong and China.

Feng shui expert

But last October the project was the first major infrastructure plan to be rejected by Hong Kong on environmental grounds.

The company is now appealing, and has even paid a Chinese feng shui expert a reported $12,000 to support its case that the railway must be built through the valley.

With a population of seven million and almost all the available land already developed, the pressure on Hong Kong's environment is intense.

Rising pollution levels and environmental degradation have become a major concern for many local people who are demanding a better quality of life.

Pressure to develop

Hong Kong's government is now concerned that the city's problems are harming its attractiveness as a international business centre.

In October 1999, Hong Kong's Chief Executive Tung Che Hwa pledged to clean up the city.

But there is also pressure to develop new infrastructure, in particular new links to China.

As Hong Kong becomes more closely intertwined with the economy of southern China, tens of thousands of people and large amounts of goods are crossing the border every day.

The decision whether to build across Long Valley will test whether it is the environment or development that is the priority in Hong Kong.