Two-thirds of British primary schoolchildren have at least a second cousin in at least one other Commonwealth country, estimates show, yet many people do not know what the Commonwealth is.
This year has been designated the UK Year of the Commonwealth and, in a bid to raise its profile, scores of events, co-ordinated by the Royal Commonwealth Society, are taking place throughout Britain to help alter misconceptions and shake off old imperial connotations. A Commonwealth information pack has been sent to all schools.
But with Britain's future increasingly lying in Europe, what relevance does the Commonwealth really have today?
A good deal, according to Peter Williams, director of education at the Commonwealth Secretariat from 1984-94. He claimed Britain gains much from being a member of the oldest international organisation in the world, not least in terms of political influence.
"All the Commonwealth countries have votes at the United Nations," he said. "If we're trying to advance what we think are sound policies in the UN on the environment, the resolving of disputes and so on, then these countries are our ready-made allies. They speak English. They have education systems like ours. It's very easy for us to work with them."
One of the Commonwealth's most important roles in recent years has been that of peacemaker, and the association also fosters technical co-operation between countries.
But its effectiveness is severely hampered by lack of funds, saidMr Williams. Britain contributes30 per cent of overall funding, yet this is only a tiny proportion of the total aid budget. Far more goes to European organisations.
One consequence of Britain's decision to throw itself more into the European Union than the Commonwealth has been the devastation of higher education, he maintained.
When Britain joined the EU, it began charging students from member countries the same level of tuition fees as home students. At around the same time, former prime minister Margaret Thatcher introduced full-cost fees for overseas students from outside the EU and wiped away subsidies that had been available for Commonwealth youngsters.
The outcome has been a huge rise in European students in this country, while the number of Commonwealth students has remained almost the same for nearly 20 years.
In 1979, there were 46,800 Commonwealth students in Britain and 7,700 from the other 14 EU countries. By 199596, however, the figures were 47,800 and 70,200 respectively.
"It has become increasingly clear that English is the world language and a lot of people want to study in the UK. But if you come from Bangladesh you have to pay around Pounds 7,000-Pounds 8,000 a year, while if you come from Spain you pay nothing," Mr Williams said.
His views are shared by Dr Peter Lyon, academic secretary at the Institute of Commonwealth Studies, University of London, who said Britain gains in political, diplomatic and economic terms from belonging to the association.
"Our markets are growing fastest in the Commonwealth. The fact that investors can deal in English with banks and legal systems that are all familiar makes the flow of business much easier," he said.
A report by the House of Commons Foreign Affairs Committee, published in March 1996, concluded that Britain has unwisely neglected its Commonwealth ties.
Here, there is a great deal of ignorance about what the Commonwealth does, yet in other parts of the world it is seen as a significant international player, Dr Lyon said.
This is underlined by the fact that countries still want to become members. Mozambique joined recently and Palestine, which is not even an independent state yet, has expressed interest. "People tend to confuse the Commonwealth with the old Empire but it's not the same at all. It's not a colonial club and you don't have to be one to belong,"he said.
How the modern grouping emerged
1949: The modern Commonwealth is founded. A conference of Commonwealth prime ministers revises the principle of membership, previously based on common allegiance to the Crown, and decides to welcome newly-independent India as the first republican member.
1950s and 60s: The Commonwealth, now committed to racial equality and national sovereignty, becomes an attractive association to many new nations emerging from colonisation. There is considerable expansion of membership, despite departure of South Africa in 1961.
1957: Ghana achieves independence and becomes the Commonwealth's first majority-ruled African member.
1965: The Commonwealth Secretariat is set up to be the association's own independent civil service, with an international staff headed by the Commonwealth Secretary-General.
1971: Leaders adopt the Singapore Declaration of Commonwealth Principles which gives the association a formal code of ethics and commits members to improving human rights. They also establish the Commonwealth Fund for Technical Co-operation to advance technical co-operation between developing countries.
1991: The Harare Commonwealth Declaration sets democracy and human rights high on the agenda, giving priority to providing assistance to countries trying to establish democracy by helping draft legislation and review and amend electoral procedures.
1990-mid 1996: The Commonwealth observes around 18 elections or referendums to help democracy take root.