Rising prices have been the norm for most of the past hundred years, which has embraced two (inflationary) world wars and the great inflation of the 1970s.

That episode was sparked by rising oil prices and policy errors following the collapse of the post-war fixed exchange rate system.

Today the big story about prices is that they are falling. Again the oil price is in the lead, but in the opposite direction, having more than halved, from over $100 (£65) per barrel to around $60.

But it is not just oil. Food prices are also falling, both on world markets and on the supermarket shelves.