The north is coming. If Scotland departs the union, it will be the north, not Wales, that is next for a crisis of regional identity. How will it deal with the blood-sucking maw that has replaced Cobbett's Great Wen as metaphor for booming London?

Next week Martin Wainwright, former northern editor of the Guardian, takes to BBC radio to debunk the various "myths of the north". He follows the BBC's Evan Davis, whose TV series, Mind the Gap, breaks every record for egocentricity with no northern inch spared his southern self. Meanwhile Lord Adonis has called for the House of Lords to be moved "up north", presumably to give custom to his other madcap idea, that £50bn be spent on HS2. His fellow peer, Lord Howell, wants fracking relocated to the north's "desolate regions".

The north-south divide always brings out the whimsical Tolkien in southerners. When the BBC moved its sports and children's department to Salford, it was as if playing games and having children were "what they did up north". Davis roamed quaint Calderdale and interviewed Welsh Street Liverpudlians about dreadful conservationists. How does he think Hebden Bridge, fashionable core for his Manchester-Leeds "hub", has prospered while other mill towns died? The answer is that it did not smash itself to pieces, as did much of Liverpool.

Davis's series at least faces the north-south gap head-on. London is indeed devouring the national wealth. It is larger than the next eight English conurbations combined. As a result it draws to its core not just wealth but population, enterprise, infrastructure, migrants and culture. There is no comparison between it and the others. London is a humming, exhilarating global city. Its buildings are handsome; its housing desirable and therefore expensive; its shops, theatres, restaurants, media and intellectual life stimulating. No wonder the world beats a path to its door.

The undeniable gap cannot be healthy. It strips the north of investment and talent and thus hinders its growth. Large fiscal transfers are needed to compensate. London's political clout draws to it every privilege. Its citizens benefit from almost £650 a head of public transport investment a year, against some £250 devoted to the north. Arts spending is heavily weighted towards London. Media attention is almost exclusively London-focused.

Even current public expenditure shows rich areas benefiting at the expense of poor ones. Figures for the next two years of austerity published in Public Finance magazine show cuts in the north-west of 6-8%, with spending actually rising by more than 2% in the richer parts of the south-east. When London wants a garden bridge, George Osborne snaps his fingers and the taxpayer "donates" £30m. That does not happen up north.

Davis is right that to draw prosperity away from a "city state" such as London requires a critical economic mass, one where a multitude of activities rub shoulders with each other. But he blows his argument with the "4G fallacy", that the internet has superseded the need for human concentration. If that were true, commuting into London would be dwindling, not soaring. His idea of a "linear hub" across the Pennines lumps together Lancashire and Yorkshire and thus helps resolve the old southern problem of which "north" you are talking about. But it is no more than a London dinner party conceit.

Big cities do not work like that. Even in polycentric Europe, Barcelona struggles to rival Madrid, Rome to rival Milan, and anywhere in France to rival Paris. The magnetic force of London lies not in its suburbs – its "feeder" towns such as Croydon, Ealing, Greenwich – but in its core, a physical congregation of streets, institutions, social and artistic networks, all fuelled by a daily buzz of events and all within easy walking or travelling distance of each other.

It is plainly unfair that London is showered with privileges, with disproportionate transport grants, a puny local tax base and a cultural plutocracy. But the answer is not a confederacy of online pseudo-hubs. If provincial England is ever to challenge London, it must choose one of its own as powerful "second city", with a magnetic core fit for purpose.

Manchester city centre. Photograph: Christopher Thomond for the Guardian

This must be Manchester. It is the biggest city in the north, with new investment in group headquarters, health, education, media and culture. Its productivity is second only to London's. Manchester can draw on the most urbanised region in Europe, south Lancashire, with rich suburbs to the south and poor ones sorely in need of renewal to the north. It has a handsome centre with an emerging funky neighbourhood in the Northern Quarter and Tribeca-style warehouse flats along the canal corridor.

Urban counter-magnets demand tough choices. I would decentralise half of Whitehall to Manchester, and not just back offices. I would certainly move "Airport City", a new town designed to attract East Asian money and planned for the prosperous southern suburbs. It will consume a quarter of the city's green belt and divert resources from where it should be, in the depressed northern sector. The whole point of London's Canary Wharf was its location in the East End.

Meanwhile I would throw research projects at Manchester's universities and hospitals, subsidies at its orchestras, and heritage grants at its historic buildings. If the government really needs to spend £50bn on railways, I would give Manchester a proper underground tube, like proper big cities abroad, and do something for its dire regional road and rail links.

Leeds, Liverpool, Newcastle and Birmingham will doubtless protest such pre-eminence for Manchester. But non-metropolitan England must choose. If it is serious about "minding the gap", the only way is Manchester.