Grim though the reality is, whenever Northern Ireland has dominated the British news bulletins in the last 50 years, it’s rarely been for good reasons. So it was this morning when Arlene Foster – a woman who just a few months ago was the public face of a £500m renewable energy scandal – was pictured standing outside No 10 Downing Street, reading out UK government policy.

Who would have thought, even in these unpredictable times, that when Theresa May’s former Chief of Staff Nick Timothy was writing the Conservative manifesto, he would end up watching from the comfort of his own home as the DUP leader crossed out the bits of it they decided they didn’t fancy?

The consequences are serious for so many reasons.

The people, it is generally agreed, have had enough of politics and politicians. For some time, voices from all over the political spectrum have made similar noises: that trust needs to be re-established, the people reconnected with a political class too often seen as somehow distant and elite.

DUP announce agreement to form minority government with Tories

So what is the ordinary voter meant to make of the deal Theresa May has just made with the Democratic Unionist Party, whose neanderthal social views have proved to be no barrier to them securing £1bn worth of sweeteners in return for seeking to guarantee the hard version Brexit the ordinary voters rejected?

Since becoming Prime Minister last July, constant U-turns notwithstanding, Theresa May has governed in an almost refreshingly straightforward fashion. She took her time figuring out what Brexit means, deciding in the end that Brexit means not just Brexit, but leaving the single market and the customs union too. She laid it all out in a well-received speech at Lancaster House. She put this vision of Brexit to the country in the form of a general election, telling voters on dozens of occasions to “strengthen my hand” in the negotiations with Brussels.

When voters decided very clearly that they did not want to, the answer has been to hand £1bn of their money to Northern Ireland to allow Theresa May to ignore them.

It is hard to recall, at least in the UK, a more blatant example of pork barrel politics. An extra £400m for health in Northern Ireland, £150m for superfast broadband.

And that is far from the only bill. The winter fuel allowance will remain non-means tested across the UK. The axe on the pensions’ triple lock will not fall. These two things alone will cost £15bn.

Mark Steel: Wondering what the Tory-DUP deal will actually look like? I've got a pretty good idea

It is tempting to wonder whether, had these things not appeared in the manifesto in the first place, Theresa May might well have won the majority she sought. Meanwhile, younger voters, who backed Jeremy Corbyn in large numbers despite Labour promising to do precisely nothing about intergenerational unfairness, will bear the massive financial burden of this decision too.

The crucial question, though, is will it even work? Under the terms of the deal, the DUP will support not just the budget, the Queen’s Speech and any potential motions of no confidence, which are the usual requirements of a “confidence and supply” arrangement, but it has said it will support Brexit-related legislation too. There will be a lot of this; it will be complex and contentious.

The parliamentary maths remains foreboding. With the speaker, deputy speaker and the non-sitting Sinn Fein MPs removed, Theresa May’s minority government should have 327 votes. A combination of Labour, the Liberal Democrats, the SNP and others makes 314.

Why the DUP is so controversial

£16bn worth of promises later, it will still only take a smallish Conservative Remain rebellion to destabilise the central mission of this government. The DUP may no longer hold the balance of power, having sold it, but it means the likes of Ken Clarke and Anna Soubry on one side, and Kate Hoey and Frank Field on the other, may hold it.

Labour and Liberal Democrat peers have also suggested that the DUP deal means the “Salisbury Convention” – that the Lords will not ultimately obstruct any legislation in a government’s manifesto – does not apply.