The summoning of Fu Ying, China's former ambassador to the UK, to the Foreign Office in London over the execution of Briton Akmal Shaikh last year marked a low in foreign relations between Britain and China. Fu, now vice-foreign minister, had been a popular figure in Britain. She was at the center of a diplomatic row when Sino-British relations turned frosty.

British Prime Minister Gordon Brown's announcement on Tuesday the general election would be held on May 6 brings these relations into focus once again. The poll could herald the first change in government since just before the handover of Hong Kong in 1997.

A new government led by David Cameron, the 43-year-old Conservative leader, has already signaled there might be a change in foreign policy. He has said Britain should have a "solid but not slavish" relationship with the US and build stronger ties with emerging economic superpowers such as China.

Whether there is any substance to this claim remains to be seen should he get the keys to Number 10 Downing Street. The current Labour government led by Brown has had recent difficulties with China.

Apart from the row over the execution of a British citizen convicted of drug trafficking, there was also the episode of British Environment Minister Ed Miliband accusing China of "hijacking" the Copenhagen climate change conference only days earlier.

The two countries, however, are far from daggers drawn. Only a few weeks ago Miliband's brother, Foreign Secretary David Miliband, was on a visit to Beijing where he talked of developing a "modern partnership" with China. What he was saying appeared to be a restatement of "The UK and China: A Framework for Engagement" published a year earlier.

What exactly is meant by "modern" is difficult to decipher, although it seems to imply that you can still be friends, even if you fall out occasionally, as if Britain and China are in some form of co-habiting relationship. Whatever such fashionable terminology may mean, Brown has earned a lot of respect from the Chinese leadership for the way he appeared to lead the international response to the economic crisis when the US Treasury seemed to be run by headless chickens.

Britain and China are not countries unknown to each other. China suffered the ignominy of defeat by Britain in the Opium Wars and lost Hong Kong in the process. And despite the British being responsible for looting the Summer Palace, China has held no long-term ill will.

The UK, on the other hand, was quick to recognize the People's Republic of China - in 1950 - and has had an ambassador to the country since 1972. There is an essence a mutual respect between them, both having ancient civilizations (although Britain's is less old) and both sharing a certain wariness of outsiders.

The modern relationship is built around trade. Britain's bilateral trade with China stood at $39.15 billion last year. The UK's exports to China were worth $7.88 billion and it imported $31.28 billion, resulting in a significant trade deficit of $23.4 billion. The UK, though, had a small surplus in services of $1.19 billion. Its services exports to China were worth $2.471 billion and its imports from China $1.27 billion.

Britain claims to be the largest European Union investor in China with $16.37 billion injected in the country at the end of last year, just a nose ahead of Germany's $16.3 billion.

Although there might be a trade imbalance between the two countries, Britain maintains a leading position in many industrial sectors and it is the know-how and expertise of these companies that China still needs.

Something else that could cement the UK's future economic relationship with China is the huge number of Chinese students studying in Britain's universities, some 75,000. At Oxford University, Chinese students are the biggest foreign nationality group after Americans.

William Hague, who is likely to become foreign secretary if Cameron wins the election, said recently that Britain needed to strengthen its relationship with China. But no matter which government is elected, it will want a closer bond with China. The British know the relationship will become more unequal as China is set to emerge as the world's largest economy some time in this century. Even if the UK returns to the economic success it enjoyed before the economic crisis, it is likely to drop out of the world's top 10 economies because its population is dwarfed by those of China, India, Brazil and Russia.

That is the reality. Britain, however, does not want to compete with China. Its vested interest and that of the developed world relies on China continuing its economic success, whatever other political differences may surface from time to time.

The author is a former House of Commons-based lobby correspondent.