It has now been 18 months since disruptions to global supply chains and the war in Ukraine have triggered unprecedented inflation rates, that have only recently started to ease. While much has been written about the detrimental impact soaring bills and food prices have had on households, less is known about how this has played out across the country. 

A clear-cut geography: the pressure on costs has been particularly high in the North of England.
Inflation has been worryingly high across the UK since early 2022. But some places have been hit harder than others and it is the UK's poorest cities – those that were the least able to cope – that have borne the brunt so far – most of them in the North. 
Looking first at the most commonly used inflation metric – which measures year-on-year increases in prices – when it peaked nationally at 11% last autumn, it reached more than 13% in Burnley, Blackpool, and Blackburn. This was more than three percentage points higher than levels seen in cities in the South-East like London, Cambridge, and Reading. 
These spatial disparities then persisted over time. By April this year (the last point for which city-level inflation data is available), year-on-year inflation was still more than two percentage points higher in Burnley than in Reading. 
In cities like Burnley and Blackpool, prices have gone up by almost 20%. 
But the true scale of the pressure on costs becomes even more pertinent when comparing average prices – not to what they were a year ago which is what headline inflation figures do – but to what they were back when the crisis started in January 2021. 
Take Burnley: by April 2023, prices were on average 20% higher than they were back in early 2021. To put this into perspective – in a hypothetical situation where the price of all goods increased at the same rate – that is a block of butter going from, say, £2 to £2.40. Or the price of an average pint going from £4.50 to £5.40. 
Here too, the North-South divide is clear-cut: nine of the 10 places with the highest average price increases since January 2021 are in the North or in Scotland, with Glasgow, Blackpool and Bradford closely following Burnley. 
By contrast, London, and other cities in the Greater South East like Reading and Cambridge, sit at the other end of the spectrum.  
Consumption and spending patterns explain this North-South divide.
Income distribution is at the heart of these spatial disparities. Poorer households spend more of their disposable income on essentials, like energy and food, which makes them more vulnerable to soaring prices. This largely explains why cities outside the Greater South East, that tend to be poorer, have been hit hardest by the cost of living crisis. 
But there are place-specific factors, too. An example of this is car usage. Due to the quality of public transport in the capital, Londoners rely less on cars to get around than most people in the rest of the country, making them less exposed to increases in fuel prices. 
The energy-efficiency of housing stock is another example. The leakiest, least-insulated stock tends to be concentrated in the North of England, which pushes energy demand – and energy bills – up. 
Both of these points have important implications for the next few months, even as the rise in prices starts to ease. They mean that for as long as inflation is driven by the price of essentials – be it energy or, increasingly, food – households in the poorest parts of the country will continue to bear the brunt. 
That said, the next phase of the crisis might be different, as Londoners and people in the South East of England, where house prices are higher, are more at risk of being financially stretched by the mortgage crunch. This could blur the spatial disparities in any future analysis of rises in the cost of living.  
Weak real wage growth is the other side of the story.
Inflation is only one side of the coin. The other one is wages. For the best part of the last 18 months, average pay levels have failed to keep up with rising prices. This has had very concrete monetary implications for people's spending power and living standards. 
Research published by Centre for Cities last year showed workers in the North, Midlands and Wales were on average £131 a month poorer compared with mid-2021, and those in the South were £103 worse off. 
The last update of wages data at the local level showed real wages were still shrinking across all 63 cities and large towns by April 2023. 
This was particularly acute in cities like Wigan, Telford, and Newport, which experienced both weaker nominal wage growth and high inflation, driven in large part by the rising price of food. 
There are early signs the tide might be turning. National wages data, published recently, showed year-on-year wage growth in June had narrowly overtaken annual inflation for the first time in 18 months. This is glimmer of good news. 
We now need to wait until the next wages data update at the local level, in October, to see how this is playing out across the country. 
Wage rises vary by sector, so if wages are rising at the highest rate in finance and digital sector jobs, for example, and at a lower rate in public sector and local services roles, then those places where more people work in public sector and local services roles will feel the impact of the cost of living crisis for longer.
With inflation easing and wages going up, perhaps many in Whitehall will feel like this is the beginning of the end of the cost of living crisis. But they shouldn't get carried away: here too, moving the cursor from year-on-year changes to a January 2021 baseline shows both prices and wages are still far from their pre-crisis position. 
In all the 63 cities and large towns Centre for Cities looked at, real wages were still down on their January 2021 levels. 
The Government's strategy, so far, is to bring a short-term response – to halve inflation by the end of the year. But beyond this, the next most important and more daunting task for Government is to learn the lessons of not only the past two years, but the past two decades. 
This shock shows how exposed certain places are to rising energy and food costs, and widens already existing spatial disparities. 
Policy should be acting now to insulate them from future shocks. That is not a short-term fix. It can only be done by boosting wages and economic growth through long-term investment in places, reversing long-term trends of productivity stagnation, and focusing on increasing the level of prosperity in parts of the country that need it the most.