Regular readers of this column will know that I have maintained a broadly constructive tone for GBP exchange rates. This has been largely correct. Despite the plethora of bad news reports in recent years, GBP has not depreciated aggressively as many analysts predicted. My rationale for expecting GBP to perform relatively well was that it traded at a very compelling valuation according to the standard valuation metrics which most currency analysts use, and the decline in UK political uncertainty (avoidance of a Corbyn led government) provided an upside catalyst for GBP gains. However, a number of recent developments have led…