KAMALESH SHARMA, the Commonwealth’s secretary-general, reckons he has the “most spectacular office in London.” Through one window he views St James’s Palace, stolidly Tudor; through another the royal park and Whitehall, sparkling on an autumn day. Mr Sharma, a retired Indian diplomat, also has a cushy job. It comes with a Mayfair mansion and, for an accomplished but laid-back grandee, nothing too demanding to do.

The big achievement of the Commonwealth, a 54-member club sprung from the British empire, is its existence. Its current guise dates from 1949, when an alliance of Britain and a clutch of former colonies was rejigged to allow India to remain a member despite its plan to become a republic. Since then almost every former British colony has signed up to a club that retains the British monarch as its head. The Commonwealth runs a decent sports championship but is otherwise cash-strapped, unsure of its purpose and increasingly obscure. In a recent poll, half of Britons and Canadians could not name any Commonwealth activity. A quarter of Jamaicans thought Barack Obama was its head. Yet over the horizon, in Westminster, there is a rising threat to Mr Sharma’s peace.

As Britain inches towards the EU exit, many Conservatives wonder whether the Commonwealth might provide the template for an alternative trade regime. The idea is steeped in history. Britain’s decision to join the European project in 1973 led to the abandonment of a system of reciprocal trade terms, known as Commonwealth Preference: henceforth French, not New Zealander, farmers would enjoy favourable access to British markets. For a certain sort of Tory traditionalist, this was an egregious betrayal. But it is not only empire nostalgists who dream of renewing the Commonwealth. Europe is debt-ridden and destined for slow growth. The Commonwealth, which spans five continents and encompasses nearly a third of the world’s people, is projected to grow at over 7% a year. Some fervent Eurosceptics consider this an opportunity that Britain, freed of its EU bonds, would be much freer to exploit. Even cooler heads talk up the Commonwealth. Last year David Cameron, the prime minister, lamented that Britain had forgotten “old friends” while diving into now-shrinking European markets. His foreign secretary, William Hague, claims to be putting “the C back into FCO”—that is, the Foreign and Commonwealth Office.

Mutual proficiency in English and common contract law mean Commonwealth members are unusually likely to trade with each other. They are also likelier to be democratic (hence stable) and less corrupt than their non-Commonwealth neighbours. Nine of the 15 African countries to achieve credit ratings are Commonwealth members. By one estimate, the average cost of doing business inside the club is 20% less than outside it. As the world’s sixth biggest trader, Britain already benefits from this so-called Commonwealth advantage. The sum of its exports to the Commonwealth—£54 billion ($86 billion) in 2011—is less than a quarter of its European trade, but it is growing at over 10% a year.

A few even dream of turning the Commonwealth into a giant free-trade zone. This would require exiting the single market as well as the EU. But it is at any rate mere fantasy. Commonwealth countries’ use of English and vague feeling of familiarity would make them no more likely to sign up to such a scheme than any other collection of diverse economies. India’s habit of obstruction at the WTO is a clue to this: Indian farmers are more numerous and protected than French ones. “To form a formal trade block would be difficult,” Mr Sharma says politely. “Because where is the commonality?”

There are more plausible suggestions to leverage the Commonwealth trade advantage—albeit none that runs contrary to Britain’s EU membership. They include creating a Commonwealth Investment Bank, a Commonwealth business visa and a “Made in Commonwealth” kitemark. The government also talks of reforming the 70-plus dysfunctional Commonwealth institutions that Mr Sharma oversees, which are most obviously adept at providing junkets to his several hundred staff.

The bonds of history

Yet there is a problem. Britain and its close Commonwealth allies, Australia, Canada and New Zealand, provide over two-thirds of the Commonwealth’s running costs—but they cannot reform the Commonwealth. The club works on the basis of consensus, and almost any suggestion they make is liable to draw allegations of neo-colonialism. This is most evident in their separate efforts to promote so-called Commonwealth values. Over half of Commonwealth members use capital punishment; many African ones retain anti-sodomy laws. A recent British-led effort to institute a Commonwealth commissioner on human rights, democracy and the rule of law was shot down by Nigeria and Sri Lanka, backed by India and South Africa.

Reform of the Commonwealth would require leadership from its biggest third-world members. But none is interested in providing it. Commonwealth dreamers underestimate the extent to which these countries remain burningly resentful of a colonial past of which the Commonwealth will always issue a reminder. The best balm to this resentment, paradoxically, is the queen, for whom Commonwealth leaders show an almost reverent regard. Yet they also see little or no advantage in Commonwealth membership that they do not get from the myriad other clubs to which, these days, all belong.

In 1949 India was an anxious new country with an agrarian economy; now it is rich, nuclear-armed and demands a seat on the UN Security Council. India’s foreign ministry has not a single working group dedicated to the Commonwealth. “They might set one up if I asked them,” mused Mr Sharma. “They probably think I’m their bloody working group!”