Let us put matters into perspective. Inflation in the UK remains pretty low, but it has been above the target for most of the past five years, recently by a fairly large margin. Moreover, at 3.1pc, core inflation is higher here than in both the US and the eurozone, where it stands at 0.9pc.

The simple explanation, which I favour, is the influence of one-off factors. The most important is the fall of the pound, followed by the restoration of VAT to 17.5pc. But this view has to contend with the fact that those who espouse it have long been forecasting that inflation would come down - only to be confounded by inflation staying obstinately high.

There are three explanations, each of a darker hue. The first is that the excess capacity which is supposed to be forcing inflation down does not in fact exist. Before the financial crisis, the economy was running above its sustainable rate and the crisis itself caused a loss of capacity.

Yet why should this affect the UK and not the US and the eurozone in the same way? After all, each suffered from roughly the same size of economic downturn. Moreover, the evidence of excess capacity is pretty plain in the UK - especially in the labour market, where the unemployment rate is almost 8pc.

The second explanation is that even if there is excess capacity, for some reason it is not reducing inflation.

One possible cause is that for many firms, as demand falls, their unit costs rise. The natural response to this would be to raise prices to maintain profits.

One interesting variant of this is that businesses often refuse to cut prices, or even raise them, in the face of weak demand because they are short of cash. We know that demand is more responsive in the long run than in the short run. If firms cannot easily get finance from the banks then they cannot afford to think about the long run. They must, as a matter of survival, concentrate on the short run - and that means keeping prices high to generate cash, even though demand has fallen.

The third explanation is that expectations of future inflation have become dislodged. And when setting prices - and even wages - people are supposed to think about what is going to happen to inflation in the future. Candidates for what may have dislodged inflationary expectations include the experience of inflation being above the target for so long, the policy of Quantitative Easing (QE) which many people describe as "printing money", and the idea that the government is in such dire straits that inflation is covertly being used as a way out of its debt problems. I am decidedly unconvinced by this explanation. At least at low inflation rates, past actual inflation seems to have a more potent influence than expectations of the future. And note: this time wage increases have remained subdued.

David Fuller's view Choose your explanation from what Roger Bootle describes in his third paragraph above as factors of "a darker hue." I think he has correctly identified the various causes of higher inflation over time. Unfortunately, the cost of many items that we require on a daily, weekly or monthly basis often show the higher rates of inflation. Has anyone else living in London noticed how much more fresh fruit costs, on average, compared to a year ago?

Interestingly, most long-dated government bond yields are indicating the opposite of an inflationary risk. I will contribute my own factors of a darker hue as an explanation for the current declines in yields for 10-year UK Gilts, Euro Bunds and US Treasury Bonds. People hear that our greatest risk is deflation and buy government bonds if they believe it. Governments remain ready and willing to buy their own debt via quantitative easing. Commercial banks continue to borrow from their central banks at short-term rates just above zero and leverage up in long-dated government debt, recapitalising themselves via the yield curve. Momentum investors may be agnostics on the inflation versus deflation debate but buy long-dated government bonds because the yield is falling. Of a lighter hue, countries which have trade surpluses with the USA usually recycle excess dollars back to the States by purchasing short to medium-duration Treasuries.

All of these factors combine to create a self-feeding trend which presumably continues until either the deflation advocates declare analytical victory and say: "I told you so," or confidence returns and someone proclaims: "the Emperor has no clothes."

I think that the latest declines on these weekly 10-year yield charts for Euro Bunds (also called Euro Generic Government Bond), UK Gilts and US Treasuries look somewhat overextended. I think they represent poor value, especially when one can buy shares yielding approximately twice as much, as I have done recently for my personal long-term investment portfolio. However, on looking at the charts above, I have yet to see evidence that the declines are ending, with the possible exception of the recent loss of downward momentum for Bunds, although this is far from conclusive.