For 100 years, Hong Kong Customs has been our first line of defence against tax evasion, smuggling, piracy, drug trafficking, counterfeiting and much more. Without the dedication, commitment and determination of the department, Hong Kong would not be the modern, law-abiding international city we see today.

On this day in 1909, the "Preventive Service", the precursor to the Customs & Excise Department, was established. Its staff of five European officers and 20 local searchers set about their single mission - revenue protection on liquor.

This was even before the first flight had taken off from Hong Kong and six years before Kai Tak airport opened for business. Today, perhaps the most visible public image of the Customs Department is at Hong Kong International Airport where an endless stream of passengers decides whether to go through the red or green channel.

Add to this the 40,000 vehicles, 450,000 land crossings and more than 1,000 ships in and out of Hong Kong each day, and you can understand that customs officers have their work cut out.

From its modest beginnings, Hong Kong Customs has become a major law-enforcement agency with a team of over 5,500 officers. And let's not forget "man's best friend" - the 45 detector dogs trained to sniff out drugs and explosives.

A century ago no one could have imagined the wide and complex range of responsibilities that dominate the work of customs officers today. Cyber crime, intellectual property protection and counter terrorism are all part of the job.

Even in the early days, it didn't take long for the benefits of the Preventive Service to become clear. Soon after its launch, the Service was tasked with preventing tobacco smuggling, implementing import and export controls during World War I, and the control of dangerous drugs.

During the Great Depression of the 1930s, Hong Kong introduced a preferential tariff system to stimulate the economy. This marked the start of the Preventive Service's long association with the promotion of multilateral trade.

After changing its name to the Customs & Excise Service in 1977, it became an independent department in its own right five years later.

And since 1997, Hong Kong has remained a separate customs territory with individual membership of the World Customs Organisation. This is a great example of 'One country, two systems' at work.

The Department has a well-earned and hard earned reputation for efficiency and quality of service. And in recent years its effective enforcement of intellectual property rights has won widespread acclaim.

I am also impressed by the Department's vigilance and success in combating drug trafficking. The government has recently launched a new campaign against drug abuse, especially among our youngsters. Hong Kong Customs has an important part to play in eliminating the scourge of drugs in the city.

I warmly congratulate Hong Kong Customs on its centenary. Officers have brought distinction and honour on our city. I am confident the department is in great shape to meet future challenges and that officers will continue to serve the people of Hong Kong with "commitment and excellence".

Chief Executive Donald Tsang gave this address at the Customs & Excise Department's centennial cocktail reception at Hong Kong City Hall.