THIS summer visitors to London will enjoy smart passenger carriages on HS1, Britain’s only high-speed line, which runs from the Channel Tunnel to the capital. They can then travel to the city’s exurbs in new trains thanks to the Thameslink programme, a £6.5bn ($8.5bn) publicly funded project. Next year London’s east-west Elizabeth line, costing £15bn, will open. But if they venture far beyond the capital they will discover infrastructure that looks like it is from another, much poorer country. Many local railways are still operated by noisy and bumpy Pacer trains, converted from bus shells on the cheap in the 1980s.

The divide was highlighted this week by a series of ill-timed official announcements. On July 20th Chris Grayling, the transport secretary, unveiled plans to cut back projects to electrify railways in south Wales, the east Midlands and the north of England. Just four days later he gave his support to Crossrail 2, yet another new underground line in London, which may cost as much as £31bn. That prompted howls of indignation outside the capital. Andy Burnham, the newly elected mayor of Manchester, said he could “simply not accept” that spending billions more on transport in London was the “highest priority”.

The moans are understandable (see chart). Between 2016 and 2021, over four times as much per person will be spent on transport capital projects in London as on those in northern England, according to IPPR North, a think-tank. Include day-to-day spending and the divide is still there, adds Luke Raikes of IPPR North. Since 2005 there has been twice as much public spending on transport per person in London than for Britain overall.

Things are not quite as unfair as these figures may suggest, says Paul Swinney of the Centre for Cities, another think-tank. Although public spending per person is 12% higher overall in London than Britain as a whole, the capital pays so much in tax that it heavily subsidises everywhere else. In 2015/16, people in London and the south-east paid £42bn more in tax than they got back in spending. The rest of the country received £114bn more than they paid in tax, thanks in part to government borrowing.

The reason for much of the imbalance is that the way the government decides how to allocate money tends to favour London, argues Transport for the North, a consortium of local authorities. The Treasury has used cost-benefit analysis since the 1960s to work out which projects are most worthwhile. The current version values highly the time saved by travellers. This benefits schemes in London—densely packed with high-earning workers—against projects elsewhere. Civil servants tried to scupper a project to replace the north’s ageing Pacer trains, for instance, as it delivered only 35p in benefit for each £1 of cost. Crossrail 2, by contrast, is forecast to generate £2.10 per pound spent.

This approach risks being circular: better-off places attract more transport cash, boosting their economies further—and making the benefit-cost ratios look even better for future projects. Poor places, meanwhile, cannot demonstrate much bang for each investment buck, and so are passed over, with the consequence that they fall still further behind.

The dilemma of whether to spend money where it is most needed or where it will have most impact is an old one. But the balance could be tipped by the new regional mayors, such as Mr Burnham, who can bring more attention to the divide between London and the rest. Most are Labour and vocal in their criticism of the Conservative government.

Transport for the North now hopes to persuade the Treasury to consider the wider productivity benefits of new infrastructure in its cost-benefit calculations. As the devolution revolution takes off, expect more noise about this down the line.