What do David Cameron, Nick Clegg and Ed Miliband have in common? One thing shared between them is the way in which they pronounce class. They rhyme it with arse, rather than ass. Whenever they open their mouths, all three party leaders announce that they are from southern England.

The Prime Minister is an Oxfordshire Tory. The Lib Dem and Labour leaders have Yorkshire seats, but neither possesses the matching accent. Mr Miliband was born and largely bred in London. Mr Clegg came into the world in the not so gritty streets of Chalfont St Giles, Buckinghamshire. To a true northerner, they are no less southern than David Cameron.

The great majority of the decision-makers at Westminster have their roots in the south. When Oliver Letwin was trying to persuade Boris Johnson of the case for green taxes on aviation, the cabinet minister told his fellow Old Etonian: "We don't want more people from Sheffield flying away on cheap holidays." He could have made his point by referencing Southampton or Salisbury. It tells us something that it was the folk of a northern city that came to Mr Letwin's mind when he wanted to deny discount travel to the less well-off.

With the exception of William Hague, Eric Pickles and two Lib Dem Scots, the cabinet is a very southern English affair. This may not have been much noticed by the south, but it is very evident if you look through the other end of the telescope. Viewed from Leeds or Manchester or Newcastle, Westminster is more remote than ever. It also seems increasingly hostile. Northern England has a growing – and often legitimate – grievance that it is getting a raw deal compared with the rest of the United Kingdom. There is the historic complaint, sharpened by public spending cuts which will bite hardest in the north, that they are discriminated against by power brokers concentrated in the south. To that is now added a creeping realisation that they are also losing out in money and influence to the devolved governments in Northern Ireland, Wales and Scotland – particularly the latter.

That's the new dimension to an old tension. Elizabeth Gaskell published North and South back in 1855. There's some crudity to dissecting England like that. It's not all grim up north – far from it. Leeds is a place transformed compared with the city in which I was born. The skylines of Manchester, Newcastle and Sheffield gleam with concert halls, art galleries, university buildings, shopping malls, and other citadels of steel and glass that helped to restore the self-confidence of northern cities in the Nineties and Noughties . The Labour years appeared to soften the north/south divide, but maybe they just masked it by using public spending which has left northern England proportionally much more dependent on public sector jobs and state-financed contracts. The spending cuts are bound to be felt most severely here. That is a brutal truth that can't be sugar-coated by rhetoric about everyone being in this together.

In coalition theory, those losing jobs in the public sector will join those being levered off welfare in finding employment in a resurgent private sector. Nowhere more than the north does this need to come true if there is to be a re-balancing of the economy and an end to the squandering of human talent. The grey economic clouds are occasionally pierced by a ray of sunshine. A Thai company has investment plans which promise to more than double the number of steelworkers employed at Teeside Cast Products. Newcastle, home to pioneering work on stem cell research, has ambitious ideas about becoming the world's first "biotech city". The BBC, to squeals from some of its staff, is shifting a lot of production to Salford.

Some of the cabinet do appreciate that the north/south divide hurts the country's economic performance. Philip Hammond, the transport secretary, remarked the other day: "It is not possible for Britain to maintain its prosperity in the 21st century in an increasingly competitive global economy unless we can close the growth gap between the north and the south." He was defending – against much southern dissent in his own party – the construction of the high-speed rail link between London and points north. I'm a fan of high-speed rail, but too much expectation is being invested in one very long-term infrastructure project. The first phase is not due to connect London with Birmingham until 2026. It may reach Leeds and Manchester sometime around 2033.

In the here and now, the north feels the fight for future prosperity is unfair with the rules rigged by a coalition that appears to favour its chums in the south. Regional development agencies, one of Labour's imperfect attempts to address the north/south divide, are being wound up. These agencies own many millions of pounds' worth of land, buildings and other assets, some of which are crucial to regeneration projects that might help drive future growth. Boris Johnson has been handed control of the assets of the London Development Agency. What they'll do for the capital's Tory mayor, the government won't do for northern city halls. They have been told that they must pay market value if they want to get their hands on the assets of the agencies that are being axed.

That contrast is a source of grievance to politicians in the north across parties. Another and growing resentment is that the north of England is getting very short-changed compared with the devolved governments in Belfast, Cardiff and especially Edinburgh. The Scots, the Welsh and the people of Northern Ireland have done rather handsomely out of devolution. There are cash flows from the Treasury to buy things for their citizens not available in England, and the powers to shape their own destinies. Tyneside feels just as far from decision-making in Westminster as do Scotland or Wales, and Geordies have a sense of identity every bit as strong as Celts. But they do not have the political clout to make their voice heard in London.

Compare and contrast with Alex Salmond. To his recent election victory and accompanying proclamation that there will be a referendum on independence, the coalition has responded with soft words towards Scotland and hard cash for its Nationalist government. In terms of crude Tory electoral interest, they would be better off if the Scots said farewell. But David Cameron is desperate not to be remembered as the Conservative prime minister who lost the Union. The Scotland Bill, which completed its passage through the Commons last week, adds to the heap of advantages that the Edinburgh parliament enjoys over its neighbours in the north of England. The legislation will allow Mr Salmond to issue bonds and borrow against future business rates. That will give the Nationalist government an additional £2.7 billion of borrowing power with which to protect itself from public spending cuts or fund building projects – a power denied to English councils. The Edinburgh government's overall spending is to be boosted to £12bn.

Looked at from the north of England – or indeed by any fair-minded observer – this is grossly unfair. Income per head in Scotland is 99% of the average for the UK. Income per head in the poorer north-east of England is less than 80% of the national average. Yet Scots receive £507 per person more in government spending. Crunched between well-favoured Scottish Nationalists in Edinburgh and a southern coalition in London, the north of England has sound grounds for feeling aggrieved.

Politics is deepening the division. Labour is bouncing back in the north, but remains unconvincing to voters in the south. The Conservatives look resilient in the south, but have never managed to sell David Cameron to the north. At last year's general election and this year's local elections, the Conservatives made their strides in southern England while performing much more weakly the further you drove up the M1 or M6. There is not a single Tory councillor in Leeds, Liverpool, Manchester, Newcastle or Sheffield. Some of Mr Cameron's strategists worry about this and they are correct to do so. A divided country mocks the prime minister's claim to be a One Nation Tory. It will be very difficult for the Conservatives to secure a decent parliamentary majority on their own if they cannot win in more parts of northern England.

The disappearance of the Tories from much of the north turned the Lib Dems into Labour's main competition. The Lib Dems' northern councillors were obliterated at the local elections. Nick Clegg has confided to friends that he was slow to realise how much visceral hostility towards the Tories there was in the north, nor had he foreseen how it would be displaced on to his own party through guilt by association. It is reasonable to suppose that this trend is going to continue into the future, splitting the country between a Labour north and a Tory/Lib Dem-supporting south. This is not a happy prospect, this future for England in which it becomes ever more starkly divided into two political nations.

• The following correction was printed in the Observer's For the record column, Sunday 3 July 2011. In this article, we said there was not a single Conservative councillor in Leeds, Liverpool, Manchester, Sheffield or Newcastle. Correct for the last four, but Leeds has 21 Tory councillors.