Go to Preston and tell them that Britain is booming and the notion will be greeted with a hollow laugh.
Tell the folks in Hull that the housing market has caught fire and they will assume you have taken leave of your senses. Mention in Rochdale that a corner has been turned and you are likely to be run out of town.
Ed Miliband's big idea at last year's Labour conference was One Nation Britain. This is a nice as an aspiration but bears no relation to the country we actually inhabit.
The latest growth figures are a classic example of Disraeli's dictum that there are three sorts of falsehoods: lies, damned lies and statistics. Sure, if you take the UK as a whole it is true that growth has returned. National output is expanding by 3% a year, slightly above its long-term trend.
But the country-wide average disguises considerable regional disparities, which are reflected in Britain's political make-up. Areas where the Conservatives are strong tend to have above-average prosperity; areas where Labour is strong tend to be poorer than the average. Marginal seats are clustered in those areas where the two nations collide.
House prices are one example of how regional economic performance varies. The Office for National Statistics said last week that property was 3.3% dearer in July 2013 than it had been a year earlier. But strip out London, where the cost of a home increased by almost 10%, and the south-east, and in the rest of the country prices were up by just 0.8%. That's below inflation, meaning that property prices are falling in real terms. In Scotland and Northern Ireland they are falling in absolute terms.
Now look at the regional breakdown for workless households, where the five areas with the worst record are all former industrial powerhouses lying north of a line drawn from the Severn estuary to the Wash: Glasgow, Liverpool, Hull, Birmingham and Wolverhampton. For the UK as a whole, 18% of households do not have anyone in work; in the unemployment blackspots it ranges from 27% to 30%.
At the other end of the scale, the areas with the fewest workless households are all in the south of England. Hampshire has the lowest percentage, at 10.6%, followed by North Northamptonshire (11.2%), Buckinghamshire (11.3%), West Sussex (11.3%) and Surrey (11.4%).
The north-south divide is not new. Far from it. There has been a prosperity gap for at least a century, ever since the industries that were at the forefront of the first industrial revolution went into decline. But the disparity between a thriving London and the rest has never been greater.
On past form, there will be a ripple effect from the south-east and there are tentative signs that this may be happening. But it is early days and, understandably, there is concern in the rest of the UK when it is mooted that economic policy needs to be tightened to tackle a problem that is chronic and heavily localised.
This is well illustrated in an article by Paul Ormerod published in Applied Economics Letters. Ormerod drills down into the UK labour market to see what has been happening to unemployment at the local authority level.
He notes that most labour market economists have seen the cure for unemployment as a good dose of "flexibility".
According to this approach, joblessness will only persist over time due to "rigidities" in the labour market. Remove the rigidities – such as over-generous welfare systems, employment security provisions, working time regulations, national pay bargaining – and the price of employing workers will adjust (ie reduce) to a level that will ensure that everybody who wants to work can find a job.
That's the theory. Ormerod tests it by looking at what has happened to unemployment over time. If greater labour market flexibility is the answer, then local authority areas with high levels of unemployment 20 years ago should have witnessed an improvement. But Ormerod finds no such correlations.
Those parts of the country that had relatively high levels of unemployment in 1990 still had them in 2010, even though the rates of joblessness went up or down according to whether the national economy was booming or struggling. "The striking feature of the results is the strength of persistence over time in patterns of relative unemployment at local level," Ormerod said.
Those who say flexibility is the answer may counter that the problem with Britain is that the labour market is still not flexible enough, and that only by making the UK more like the US can the problem of persistent unemployment be tackled. The only difficulty with this argument is that high levels of unemployment persist in America as well, although the correlation is not quite so strong as it is in Britain. This, though, may have more to do with the willingness and the ability of Americans to move than it does with the flexibility of the labour market.
Ormerod concludes: "The labour market flexibility of the theorists, beloved by policymakers, appears to be at odds with reality. This is especially the case in the UK, where relative unemployment levels persist very strongly over long periods of time. The findings certainly call into question the efficacy of policies that were designed to increase flexibility and to improve the relative performance of regions."
The cross-party support for a new high-speed rail link to the Midlands and the north is one attempt to find new ways to tackle the two nations problem. Supporters of HS2 say the cost will be worth it because the new line will lead to higher investment, increased rates of business creation and enhanced spending power in the northern regions.
Another solution to the north-south divide would be for London, rather than Scotland, to get its independence. Although Britain is not part of the single currency, London is Europe's unrivalled financial capital. From the dealing floors of Canary Wharf in the east to the hedge-fund cluster in Mayfair to the west, London is where the action is. Upmarket estate agents can tell where the world's latest troublespot is by the source of the foreign cash buying up properties in Belgravia and south Kensington: currently, it is Syria.
Were the government to publish regional trade figures, they would show that London runs a current account surplus with the rest of the UK, offset by capital transfers from the rich south to the poorer north. As an independent city state, London would have a higher exchange rate and higher borrowing costs. The rest of the country would, by contrast, get a competitive boost.
The reality is that London is a separate country. Perhaps we should make it official.
guardian.co.uk © Guardian News and Media Limited 2010
image: © ktylerconk