Inflation update: what’s driving the cost of living crisis?

Prices in the UK continue to rise, with the Consumer Price Index up 9.4% in June. A closer look at the underlying data shows that more items are going up in price than are going down, suggesting high inflation could be here to stay over the coming months.

Inflation rates not seen for decades have arrived in the UK. This morning the Office for National Statistics (ONS) released the latest data, which shows the Consumer Prices Index (CPI) is up 9.4% over the past year. Wages are rising far more slowly as data released yesterday shows, meaning that British workers are seeing a rapid erosion of their real-term pay.

But what is driving inflation? This update delves into the data underlying our measures of inflation to find out.

Figure 1: Line chart of CPI, 1988-2022

Source: ONS

The recent inflation is striking in just how broad based it is. The ONS breaks down the contributions to inflation by allocating goods and services into high level categories known as ‘divisions’. Across these divisions—food, housing, transport, clothing, furniture—we are seeing price pressure. This is rare. In less inflationary times the typical pattern is for some divisions to be rising, while others are flat or falling.

The data underlying these findings—so called ‘micro data’—are individual prices collected by the ONS in shops across the country. The dataset is huge (well over 40 million prices have been collected since 1988) and allows us to take a finer look at how and why inflation is surging. For more on the data, see this page.

Delving into the micro data in normal times, we find a lot of price flux. That is, even when inflation is rising, there tend to be some shops that are cutting their prices. In other words, prices tend to ebb and flow, as the pattern of the past ten years (see Figure 2). Recently, though, a striking (and historically unique) anomaly has emerged. The lines tracking the share of prices rising and falling have diverged. There are far fewer price cuts out there. This is another measure of just how widespread the inflation is that we are facing.

Figure 2: Month-on-month price changes

Source: ONS; Davies (2022)

Inflation is an annual concept—the price today compared to 12 months ago. So, the next chart asks the same question over a yearly window. The longer window smooths out some of the monthly flux, and clearly shows periods in which price rises become more common, and inflation rises.

Figure 3: Annual price changes

Source: ONS; Davies (2022)

Another interesting angle is to look at the prices of individual goods and services. Figure 4 does this, focusing on a selection of items which price rises, across the country, were most common. The left-hand panel shows the proportion of prices that rose compared to last year. For some items, all the prices the ONS collected rose—meaning inflation would be completely unavoidable. Annual prices are up for fuels (kerosene); smokers face higher costs with rolling tobacco, cigarettes and cigars all up; ready meals and take away food (fish and chips strongly up) have risen; as have staples like milk, cheese and butter. Those seeking home improvements will be stung by high prices of MDF, kitchen units and paint.

Figure 4: Micro data – main risers

Source: ONS; Davies (2022)

The higher frequency data shows a different story, and one that is increasingly causing concern. Food dominates the list of price risers, with milk, spaghetti, baked beans, salmon fillets, bacon, lettuce, cucumber and eggs all seeing high numbers of price rises. Normally these are exactly the type of items that see a great deal of flux. This means prices being up one month doesn’t necessarily lead to annual inflation, since they could soon drop down again. But as Figure 2 above shows, with price cuts a rarity, the short-term price jumps seen in the micro data may well become locked in.