According to filmmaker Nick Francis, it is the biggest story of our time. The emergence of China as a global economic power is portrayed in the documentary When China met Africa. A preview of the film by the makers of Black Gold, brothers Mark and Nick Francis, was screened at London's Frontline Club last week.

The film is set in Zambia, one of the first African countries to welcome Chinese investment. Zambia is a mineral-rich country with vast expanses of land and only 13 million inhabitants. The Chinese investors in the film chuckle and note that they have a slightly larger population. The Francis brothers' film demonstratse the shift in global power from west to east, and questions the willingness or ability of western governments to understand the role that China is playing in Africa.

The filmmakers show the complex relationship that African countries have with China. They follow a handful of central figures: the Zambian trade minister in his negotiations with and travels to China; a Chinese entrepreneur who sets up a farm in Zambia; and a Chinese construction manager, whose company has won the tender for a major Zambian road project.

We see the Zambian minister marvelling at the speed at which Chinese infrastructure projects progress both in Zambia and in China itself, and the communication difficulties between Chinese managers and their Zambian staff, who seem amused by the fact that their superiors struggle with the basics of the English language.

It soon becomes apparent that China and Africa have one overriding mutual interest: they want development and they want it fast. While the west is dabbling in development projects, drowning in paper mountains and the principles of "good governance", the Chinese hands-on approach is leaving a permanent mark on the continent.

Not that the effects of China's economic relationship to Africa isn't being felt in the political sphere either. In Zambia, the newly elected President Sata abandoned the criticism of Chinese investors which had cost him the previous election. And in South Africa the Dalai Lama was denied an entry visa to attend fellow Nobel Peace Prize Laureate Archbishop Desmond Tutu's 80th birthday, due to Chinese pressure.

"It's a win-win situation," the Zambian trade minister pronounces proudly. But are there really no losers? The film shows disgruntled construction workers bemoaning their "unbalanced diet". Yet it fails to investigate the price of the land that the investors are buying up. There is no indication of how and to whom the costs and benefits are parcelled out. Nor is there any investigation of how land rights are settled or the role played in Africa by ancestral rights. These, it seems, are questions for another day.

"When China Met Africa" premieres in the UK on 9 October at Prince Charles Cinema, London W1, with a Q&A with the directors chaired by Jon Snow of Channel 4 News. For information about additional screenings, visit whenchinametafrica.com