It is no surprise that exchange rates reflect the volatility of the markets in general.

More surprising perhaps is the relative strength of the dollar when assessed over the whole period since the present crisis began.

Many factors are at work. Yet one of them may be that, after all, the fundamentals of the American economy really do remain stronger than those of Britain and Europe.

Where the USA retains a genuine enterprise culture, the engine of recovery, the bureaucratic EU lacks strength in depth, and the UK is undermined by disproportionate public and private sector debt.

Meanwhile, American entrepreneurs can enjoy the benefits of supplying relatively cheaply from Britain and Europe, while British and European entrepreneurs should make the most of being relatively competitive in terms of price in the US market.

Given the unpredictability of the markets, including the currency markets, who knows how long it will last?