If comparisons between the state of the world economy and the Great Depression are a useful indicator of how the recovery is progressing, ministers and central bankers from the world's leading economies should be feeling a lot better than a year ago.

The analogies between the (still substantial) unemployment lines of today and the mass joblessness of the 1930s have become mercifully less frequent.

And one area in which the drawing of parallels has dropped away almost completely is that of protectionism. In the months after the collapse of Lehman Brothers in the autumn of 2008, a precipitous collapse in the volume of world trade had observers reaching for their history books, noting that the drop-off in commerce was, if anything, faster than during the 1930s.