Sir Paul will be seen grimacing as Desperate Dan, unaware of the strength of his formidable handshake, crushes the bass player's fingers (thankfully the ones on his right hand - Sir Paul plays a left-handed guitar).

BBC: Paul McCartney to appear in final Dandy comic

But by this gauge, the currencies of virtually all low-income countries are undervalued, since prices are generally lower in these countries than in rich ones (see right-hand chart, above).

ECONOMIST: Economics focus: Burger-thy-neighbour policies | The