A random encounter with a slogan on a giant billboard in a remote village in South China left a big impression on British economist Jim O'Neill nine years ago.

During a business trip in October 2009, O'Neill decided to spend some leisure time enjoying the karst mountains along the Yulong River in Yangshuo, Guangxi Zhuang autonomous region, with his wife.

"We cycled around some villages and outside one village, we saw this massive billboard, which read 'Success in English, success in life', and this stuck with me for as long as I can remember," he said.

"That made me realize how much China wanted to learn and communicate, and why it was obviously the case that China's rise is good for the United Kingdom."

O'Neill, who was recently appointed chairman of the Royal Institute of International Affairs, which is also known as Chatham House, said the lifting of hundreds of millions of people out of poverty with the help of astonishing economic growth is China's biggest achievement in the past 40 years.

"China has had the most astonishingly long period of very high economic growth, something which the world has never seen," he said.

In 1977, China's GDP was $175 billion, just 2 percent of the world's total. Last year, it was $12 trillion－nearly 68 times more－accounting for 15 percent of the world total. In that time it has jumped from 10th position globally to second, behind only the United States.

Recalling his first trip to China in 1990, the former chief economist for Goldman Sachs said Beijing looked very underdeveloped, but still showed signs of commercialism, supported by a substantial number of street markets.

O'Neill has traveled to China more than 30 times since then, each time noting the pace of constant change in the country, with a huge rise in technology use and the service sector in recent years.

This year marks the 40th anniversary of the launch of China's reform and opening-up policy, and O'Neill describes the country's economic performance during the past four decades as "powerful, transformational and to some degree inclusive".

"'Powerful' because there are four times as many people in China earning $40,000 a year as there are in the UK," he said. "In terms of 'inclusive', even though inside China, on standard measures, there's been a widening income disparity, on a truly global basis world income differentials have actually narrowed, primarily because there is an incredible Chinese story."