When I first began analysing Gulf banks more than 20 years ago, I wrote on a piece of paper the exchange rates of the six Gulf currencies against the dollar and stuck it in front of my desk. With the exception of the Kuwaiti dinar, I could use those same rates to convert the currencies today.

Even the Kuwaiti dinar, which for most of the last 20 years has been managed against a basket of currencies, has remained within about 8 per cent of an average rate since the mid-1980s. (The dinar was pegged to the dollar for three and a half years from 2003 to 2007.)