As the economies of China and India become more powerful, energy suppliers and banks are all keen to grab a slice of their rapidly growing consumer markets.

Already, the US has sent its Treasury Secretary Henry Paulson to drum up business in India and next week Nicolas Sarkozy, the French President, will lead a business delegation from his country to the sub-continent.

Today, Gordon Brown begins his first visit to China since taking over at No 10. He will meet Chinese Prime Minister Wen Jiabao and business leaders during his tour of the country. His visit, his most far-flung diplomatic mission since he became Premier seven months ago, will also take in India.

Courting the two Asian giants has become even more imperative in light of the global credit crunch, which is slowing down Western economies. While the US, UK, Japan and much of Europe are expected to record growth figures this year of less than 3%, China is looking to notch up growth of 10.8% and India 8.4%.

Mr Brown, Westminster's Business Secretary John Hutton and Lord Digby Jones, the Trade Minister, will be joined by business leaders from 3i, AstraZeneca, Barclays, KPMG, Shell and Standard Life.

Also on the trip is tycoon Sir Richard Branson, the Virgin chief, although UK Government officials were keen to stress the prospects for Northern Rock would not be discussed.

Highlights of Mr Brown's trip will be a visit to the Great Hall of the People in the Chinese capital, a joint press conference with Premier Wen, a tour of the "bird's nest" Olympic stadium, the venue of the games in August, and a meeting in the People's University where the leaders will be questioned by locals.

In Shanghai, the theme will be environmental, with Mr Brown visiting the city's urban planning exhibition centre, which features details of the proposed Dongtan Ecocity.

In New Delhi, the PM will have dinner with his Indian counterpart, Manmohan Singh, give a keynote speech, launch a sports initiative and take part in a UK-India summit and give a joint press conference. His visit will end with a formal banquet.

During the first leg of the PM's visit, which will take in Beijing and Shanghai, it is hoped that a new target on bilateral goods and services will be set at £30bn by 2010. It is currently £20bn. A new "high-level economic and financial dialogue" with China will also be established, led from the UK side by Chancellor Alistair Darling.

Officials explained how the British and Chinese economies "complemented each other well", with the former being a world leader in services and hi-tech products and the latter a world leader in manufacturing.

"There is particularly good scope for further expansion for UK-Chinese trade and two-way investments," said one official. At present, the UK is Europe's biggest investor in China.

As the Chinese economy continues to expand and its people get wealthier, ministers hope that the demand for British expertise in retail, finance, insurance and legal services will grow, leading to a wave of new job opportunities across Britain.

Earlier this week, Mr Brown said: "I can see in the next two years a 50% increase in our trade with China. I can see thousands of British jobs, perhaps tens of thousands of British jobs, over a period of time developing from this new relationship."

Shortly before boarding his flight to China, Mr Hutton added: "We are going to China to aggressively make the case for open markets and free trade between the UK and China.

"We will be looking to significantly support British companies to increase their share of business with China."

Three bilateral agreements are due to be signed covering climate change and "clean energy", sustainable cities and education. Business deals will be signed in China and those to be sealed in India are said to be worth £3bn.

Officials spoke about developing the basis of Britain's economic relationship with China and a "global prosperity pact". They raised the issue of "sovereign wealth funds" - state-backed investors - explaining that, in return for Britain's continued commitment to open markets, the UK would welcome sovereign wealth funds to London, provided they operated on a commercial basis and were committed to transparency and governance rules operating in the UK. China's fund was described as "very large and well-resourced".

Officials made clear this issue was "not about reciprocity but mutual benefit". Britain, they explained, had benefited from sovereign wealth funds for years from many countries and this was not about extending the Chinese "a special privilege".

One official said: "We're open to international investment, but people have to play by our rules on transparency and they have to be commercially motivated." He added: "What we are saying to the Chinese is we are in favour of an open world economy, open investment, open trade flows. Within the EU we are probably the most committed country to that.

"We will press to keep the world economy open and it's important the Chinese work with us on that."

"London," he said, "is a terrific platform for Chinese companies who want to raise capital. The way the Chinese economy is changing now, there is a lot more external investment going to happen over the next 15 years than has happened in the past.

"We are open to Chinese trade flows and it's possible to take the economic relationship to another level." Read Michael Settle's reports of the Prime Minister's visits only in The Herald.

In profile:

China The world's fourth-largest country, with the biggest population, at 1.32 billion. It is in rapid transition from a tightly controlled communist economy, with state industry and agriculture, to a major world economy and international centre of consumer goods manufacture. Personal incomes are improving and inward and outward investment is rising - but tight political controls remain. Its main industries are: agriculture; mining, steel and aluminium manufacture; clothing and shoes; consumer electronics and toys; cars, ships, trains and planes. Gross domestic product is £5.04 trillion. GDP growth is 11.1%. Religions include Taoism, Buddhism and Christianity, but it is officially atheist.

India The world's largest democracy, with the second-biggest population: 1.129 billion. Once synonymous with poverty and famine, it is now a major power with its own nuclear bomb, but still has social, economic and environmental problems. Its main industries are: agriculture; textiles; chemicals; steel; IT and services. Meanwhile, Bollywood is the world's biggest film industry. Gross domestic product is £2.082 trillion. GDP growth rate is 9.4%. Religions include Hinduism, Sikhism, Islam, Christianity, Jainism, Buddhism, Zoroastrianism and Judaism. India also has a caste system which determines everyone's place in the social hierarchy.