Global economic summits have one constant – squabbling over who can attend. At the first, in Rambouillet, France, in 1975, declassified documents show that Gerald Ford, US president, was “incensed” by the refusal of his French counterpart, Valéry Giscard D’Estaing, to invite Canada. The influence of summits has been far more variable. At the peak – the Plaza accord of 1985 – a G5 gathering led to a co-ordinated $18bn foreign exchange intervention that was followed by the desired decline in the dollar. Now, as G7 finance ministers and central bankers meet in Washington, the idea that the event may have market-moving clout is regarded as laughably unrealistic.

In terms of currencies, this is the case. No G7 government, including that of Japan, has indulged in a big market intervention since 2004. With the arguable exception of France, none bothers to pretend that their words can influence freely traded exchange rates. When it comes to altering fixed exchange rates, in particular the renminbi, the G7 has a hopeless track record. This is despite some pretty unambiguous statements aimed at Beijing. In February, the G7 finance ministers said it was desirable that exchange rates moved, especially that of China. This time round, the Bank of China, unawed, has bothered only to send its deputy governor to observe.