ABove: William Lindesay attends a campaign to protect environment in 2009. Below: Lindesay shows a bag of trash collected from the foot of the Great Wall. PHOTOS PROVIDED  TO CHINA DAILY

A name card is usually a small piece of paper with a person's name, address, telephone number and professional title printed on it.

But William Lindesay, a Briton best known for his solo exploration of China's Great Wall 23 years ago, uses a garbage bag as his calling card. The cloth bag bears a set of nine simple guidelines in Chinese, which calls on people to observe while traveling or camping outdoors: "Take your own garbage home," "Pick up litter left by others," "Don't damage plants or flowers, or pick fruit" and lots more.

Lindesay calls these dos and don'ts the "Countryside Code" and always carries a "Countryside Code" bag with him in the wilderness, picking litter along the way.

"We've been promoting the Countryside Code for eight years," he said. "It's been a start against the rising tide of littering and other destructive, inappropriate behavior in the countryside."

The code, he said, is a latest development of his romance with the Great Wall.

Lindesay was born in 1956, in Wallasey, a small town in north England. His love of the Great Wall of China began when he was 11. The headmaster of his school asked students to put three books by the bedside: the Bible, a prayer book and the school atlas.

Looking at the map of China in the atlas at one night, Lindesay came across the saw-tooth-like line that zigzags through the vast expanse of north China.

"I fell in love with it immediately," he said. "I thought it would be a great journey, a great adventure if one day I could travel along it, from end to end."

Most people forget their childhood dreams and end up doing something else. "But I am one of those rare exceptions," Lindesay said.

In March 1987, Lindesay set about fulfilling the dream. He started from Jiayuguan, the west end of the Ming Dynasty (1368-1644) Wall, ran and walked eastward, and from time to time had to limp because of blisters on his feet.

Seventy-eight days later, he found himself at Shanhaiguan where the wall meets the sea, after completing an odyssey of 2,500 km.

Awed and fascinated by the grandeur of the Great Wall and its surroundings, Lindesay decided to "do something long-term to make it better."

In 1988 he married a Chinese woman, Wu Qi, who has been working as his assistant since then. The couple settled in Beijing a few years later.

Over the past 20 years, never for a day has Lindesay ceased working for protection of the Great Wall. His initial efforts involved picking up garbage on the trail.

"I first made this very simple effort to draw attention to the fact the Great Wall was being damaged," Lindesay said. "For that, I was dubbed 'the famous foreign garbage collector'."

In April 1998, Lindesay launched the first Great Wall cleanup campaign. Three years later, he established the International Friends of the Great Wall, a non-government organization based in Beijing.

The NGO has joined hands with the Beijing Municipal Administration of Cultural Heritage, UNESCO and the World Monuments Fund to boost public awareness of problems afflicting the Wall.

In recent years, an exodus to the Great Wall has created far more garbage than Lindesay and his friends can handle.

Every year about 4 million people visit Badaling Great Wall. Day after day, it is besieged by hordes of tourists and overrun with souvenir sellers.

"We became frustrated for the lack of progress," Lindesay said. "I believe it's not that people aren't contributing. It's that more and more people are going out outdoors."

That was how he came up with the idea of the "Countryside Code" to support and encourage the growing numbers visiting the countryside to play their part.

Lindesay said the rationale behind the code is the old saying: "Prevention is better than cure."

"We estimate about 75 percent of tourists visiting the wilderness litter wherever they are," Lindesay said.

"You may think that you, as an individual, can't make a real difference. I think you can."