Last Friday, Westminster showed its love for Scotland by putting up an Old Etonian MP for a safe Tory Oxfordshire seat to speak at the Olympics velodrome, paid for by the British public but gifted to east London. Truly, the Scottish Nationalists could ask for no better recruiting sergeant than David Cameron.

Forget, if you haven't already, the prime minister's burblings about "brand Britain" and our apparent monopoly on creativity and ingenuity. Such speeches simply remind us of how the imaginations of Blair and Cameron have turned British history into a Richard Curtis movie from which we are struggling to escape.

Far more revealing was the tableau. Cameron and his aides chose their location as a reminder of the achievements of Chris Hoy and Team GB. But the setting for their defence of the union was also a place that demonstrates how superbly it serves just one corner of it. Look, the prime minister might as well have said, this is what the UK is all about – taking billions of the nation's taxes and paying them to huge civil engineering firms who build structures that push up London house prices and fatten profits for property developers and local estate agents.

You will see many other such moments between now and Scotland's vote on 18 September, even if not all of them are unwitting own-goals. Any halfway serious investigation of the relationships between our nations and regions will end up showing how much of Britain's business model is built on taking wealth and power from across the country – and handing it to a small cabal of financiers and businesspeople in central London.

A giant sucking sound can be heard in the UK today: the sound of public money and private wealth being sucked down south to London. The result is the emasculation not just of Scotland, but of Newcastle, Oldham, the Midlands, and countless other places not featured on the Circle line.

The Kelvin MacKenzies of this world would have you believe that the rest of the country is subsidised by the capital. It's quite the opposite. Stroll around the centre of London: the place is a building site, full of public works. The Thames Tideway. The Channel Tunnel Rail Link. Crossrail, set to be the biggest construction project in Europe. All this building and jobs are being bankrolled by the rest of the country, yet the benefits go to London businesses. At the end of 2011, the IPPR North thinktank totted up all the government's spending on transport projects up till 2015. Londoners enjoyed public investment of £2,731 per head, far outstripping any other region. The north-east received a measly £5 per head.

The further out you look, the worse the trend becomes. When Howard Davies and his official commission reports on expanding Britain's airports, it could recommend building more capacity outside London and the south-east – but I'll bet you a 747 it doesn't. Then there is HS2, sold to the public as giving more economic opportunity to the Midlands and the north-west. Much more likely, as John Tomaney, professor of urban planning at University College London warns, is that "it will turn Birmingham into a suburb of London".

Every so often, the mask of a member of the establishment slips and they admit that spending is skewed towards the M25. But, the argument goes, Londoners are worth it. Remember Boris Johnson's declaration of 2012: "A pound spent in Croydon is of far more value to the country than a pound spent in Strathclyde." London is where the big-boy jobs are, runs this line – and the companies who create them.

Except that this ignores how the rest of the UK pays for London to enjoy that wealth. Take the public-private partnerships and PFIs used from John Major onwards to build and run hospitals, schools and transport services. Adam Leaver, at Manchester Business School, looked at 657 UK companies involved in PFI/PPP deals between 2004 and 2012. Of all these schools and other public facilities being laid on across the country, 75% of the firms operated out of London and the south-east; 83% of the revenue went to one corner of the UK.

Take St Mary's Hospital, Manchester, part of a £500m redevelopment project in that city of health facilities. The shareholders: all from London or Kent. The various legal and financial advisors: all from within the M25. Of the five contractors, only one is from Manchester.

This is no longer north v south: it's the rest of the country versus a small elite in London, on which is lavished a surplus of political attention, public funds and opportunities. Say the floods devastated not Somerset, but turned Surrey into paddy fields: can you imagine Owen Paterson waiting weeks to roll up in his smart city shoes? Count up the senior civil servant jobs outside the capital – go ahead, use all the fingers of one hand to do so. Even the commonplace view that Alex Salmond is some kind of titan of politics (he's not, as the foul-up with Donald Trump demonstrates) serves to demonstrate just how unused we are to a major regional political figure. There's only one other, one B Johnson of London. Turn Britain's regions into subsidiaries of London, raze its business and political elites, and you have hardly any counterbalance to the might of the City.

For what it's worth, I hope Scotland stays within the union. As my colleague Jonathan Freedland has pointed out, without it, the British identity will feel narrower, its politics more hard-hearted. But the debate over Scotland will inevitably underline how badly all the other nations and regions have been done over by the capital. And for that, the rest of the UK owes the Yeses of Scotland a big vote – of thanks.