The Institute of Commonwealth Studies at London University held a colloquium on Thursday July 10 on the subject of "Why join the Commonwealth?". I was invited to be a lead speaker. What follows below is a very much shortened version of my remarks given the space restriction of this column.

In recent time the relevance of the Commonwealth has been widely questioned. Many critics claim that the association is marginal to the interests of the majority of its member-states and that it has become virtually unknown among their peoples. In part, this is why the question arises of why join the Commonwealth.

But, far from having no role the 53-nation Commonwealth is today more needed than it has been since its heyday of fighting for an end to racism in Southern Africa, the independence of Zimbabwe under majority rule, the freeing of Nelson Mandela and the ending of apartheid. It is up to its leadership to make it relevant again; the potential and space for a role certainly exists.

It is more than a cliché to remind that the membership of the Commonwealth is representative of the world. It is drawn from every continent; it embraces every race and every religion; it is made up of big countries and small ones; it encompasses rich nations and poor ones. Further, its member-states are also members of virtually every regional, economic and trade organisation in the world. But, even more importantly, in the inter-governmental Commonwealth and its councils, leaders of all its member-states have access to each other for free and frank discussion in ways that are without equivalent in any other organisation.

Quite realistically, the Commonwealth is a network of networks; decisions made within it have the scope to resonate globally and to cause an impact beyond its own councils. That is the considerable 'soft' power that the Commonwealth has when used purposefully.

It should be noted that its present 53 member states, including Britain, chose to be part of the Commonwealth voluntarily, and to remain part of it. Two of these member states - South Africa and Pakistan – were withdrawn from the association by their governments at the time, but subsequent governments brought the countries back into the grouping. Obviously, they recognised that the association has value for them.

Two other countries were withdrawn from membership – Zimbabwe and The Gambia. In the case of Zimbabwe, President Robert Mugabe's government violated Commonwealth values regarding democracy and free and fair elections. When the Commonwealth sought to suspend Zimbabwe from membership because of this infraction of its rules, President Mugabe withdrew Zimbabwe from the association.

Last year The Gambiam President Yahya Jammeh withdrew his country from the Commonwealth because, according to his Information Minister, he no longer wished to "associate with Great Britain" and "will never be a party to any institution that represents an extension of colonialism". Strangely, The Gambia did not break relations with Britain. By contrast, the government of Tanzania, under President Julius Nyerere, did not withdraw from the Commonwealth in 1965 when it broke diplomatic relations with Britain over the latter's failure to act against the Unilateral Declaration of Independence by Ian Smith's regime in Rhodesia (later Zimbabwe). Nyrere kept Tanzania in the Commonwealth declaring, rightly, that it was not British.

The Commonwealth is not "British", and it has not been British since 27 April 1949, when the Heads of Government declared their countries to be "free and equal members of the Commonwealth of Nations", ending the term "British Commonwealth" – and establishing both the voluntary and equal nature of membership.

Before any government contemplates joining the Commonwealth it would have to take account of the criteria for membership established by Commonwealth leaders in 2007. Among the criteria are: an applicant country should, as a general rule, have had a historic constitutional association with an existing Commonwealth member, save in exceptional circumstances; the country must demonstrate commitment to democracy and democratic processes, including free and fair elections and representative legislatures; the rule of law and independence of the judiciary; good governance, including a well-trained public service and transparent public accounts; and protection of human rights, freedom of expression, and equality of opportunity; and the country should accept Commonwealth norms and conventions, such as the use of the English language as the medium of inter-Commonwealth relations, and acknowledge Queen Elizabeth II as the Head of the Commonwealth.

Joining the Commonwealth now is, therefore, a rigorous process and it is unlikely that, notwithstanding expressions of interest by two countries (South Sudan and Burundi), there will be any expansion of Commonwealth membership in the near future. The only exceptions to this general observation would be Zimbabwe and The Gambia where, if their governments were to rectify their record with respect to adherence to Commonwealth values, they would undoubtedly be welcomed back into the fold.

At a very practical level the Commonwealth is a very cost-effective form of diplomacy for all of its members large and small.

Consider the campaign at the moment by New Zealand for a non-permanent seat on the United Nations Security Council. Commonwealth countries are a special focus of New Zealand's campaign, as they would be for all large Commonwealth countries, such as Australia, Britain, Canada and India, when they seek support for a cause or a candidate in the international community. Fifty-three Commonwealth votes matter. So too does the influence of those 53 countries, speaking up in organisations throughout the world of which they are also members.

The Councils and meetings of the Commonwealth are cost-efficient means of a country – big or small - maintaining relations with 52 other countries that could be of help to them.

For small states, the importance of the Commonwealth lies primarily in the access Summit meetings give leaders of these small countries to leaders of some of the world's major powers on an equal basis. No other international or multilateral organisation affords them such an opportunity. But beyond access, the Commonwealth also delivers research and advocacy vital to the interests of small states.

The Commonwealth's research on Economic and Development issues, and its advocacy of agreed positions on debt, on trade facilitation, on development financing, on Global Warming and Climate Change gives every member country resources most do not have on their own, and advocacy many could not afford on their own.

Today, there are great issues that confront the world: high unemployment and restlessness of frustrated young people; growing antagonism between and within nations based on religious grounds; hegemonistic tendencies by powerful countries toward their neighbours; competition between nations for resources that are becoming scarce; an enlarging gap between rich and poor countries.

The Commonwealth of Nations cannot solve these problems, but given its diverse membership, it can make a great contribution to their solution if its diversity is managed effectively by its leadership.

(The writer is a Consultant, Senior Fellow at London University and former Caribbean diplomat. Responses and previous commentaries: