Ian Paisley never did like journalists. The fire-and-brimstone founder of the Democratic Unionist Party (DUP) reserved some of his most creative expressions of contempt for the people who dared to scrutinise the mission he prosecuted with such zeal: keeping Ulster British – and Protestant. The BBC was “infested with Papists”. The Belfast Telegraph was “lying and treacherous”. As for reporters, Paisley saw them as “whirring multitudes of pestiferous, scribbling rodents” and “spineless, brainless mongoloids”. In a world of competing certainties, journalists and their questions get in the way. To the likes of Paisley, they seem “as maliciously perilous as vipers”.

In later life, Paisley’s lurid denunciations gave way to a more statesmanlike mien. His conversion to power-sharing with Sinn Féin in 2007 ushered in a decade of devolved government that, by the time it collapsed in 2017, had almost begun to look stable, if not yet conventional. After decades of direct rule from Westminster and fitful periods of devolution at Stormont, Northern Ireland was largely running itself – and had taken responsibility for contentious areas such as policing and justice.

Paisley’s party had changed too: from bastion of unreconstructed, fundamentalist Presbyterianism to a formidable electoral machine with a broader base of support. So one naturally wonders what the late DUP leader would have made of Sam McBride’s Burned, the first book to pull back the curtain on the most secretive political party in the UK, and the great democratic experiment it helped run into the ground.

Northern Ireland has had no government for nearly three years, yet its moribund assembly has been proposed as a quick fix for the knottiest Brexit question of all: managing the Irish border once the United Kingdom, and therefore Northern Ireland, leaves the European Union. London, Brussels and Dublin have proposed that Stormont should decide whether Belfast stays aligned with EU rules, imposing the border in the Irish Sea – a solution loathed by the DUP. Could it possibly work? In his deft and engaging book, McBride, the political editor of the News Letter, Belfast’s unionist daily, reveals the answer is almost certainly no. And that answer itself poses an altogether more troubling question: is Northern Ireland ungovernable?

Before the Good Friday Agreement instituted an uneasy but enduring peace in 1998, anyone seeking to answer that question need only have pointed to an insoluble sectarian conflict, decades of paramilitary violence and a series of failed attempts to convince unionists to share power with the nationalist minority. In 2019, with the Troubles long over, McBride tells a rather different tale – the scarcely believable story of a scandal that led to the disintegration of devolution.

Paisley once called McBride’s paper “cowardly”. In taking a sledgehammer to the parochial world of Stormont, McBride proves he is anything but. His pacy account reveals that the DUP leader, Arlene Foster, her special advisers, hapless civil servants, poultry farmers, woodchip boilers and £1.2bn of public money may well have done what the Provisional IRA never quite managed and dashed any hope of Northern Ireland enjoying a functional government ever again.

In 2012, Foster – then Northern Ireland’s enterprise minister – introduced a green energy scheme called the Renewable Heat Incentive (RHI). As its name suggests, the intention was to encourage businesses to switch from grimy oil- and gas-fired boilers to biomass equivalents, powered by recycled wood pellets. Under the same scheme in Great Britain, businesses were offered subsidies to make the transition.

Stormont wanted its own slice of the pie and Foster’s department set up a Northern Irish equivalent. But, when the Westminster legislation came to be copied and pasted into Northern Ireland’s statute book, 107 words were omitted: the section that provided for cost controls. Whether by accident or design, so began four years of “cash for ash”. With the government subsidy higher than the cost of fuel, those who installed boilers could run them at a profit.

What followed was so implausible that McBride feels it necessary to assure the reader that it is all true. Absurd, grimly funny vignettes leaven a story that in lesser hands would have been a dreary political procedural. Farmers, we learn, heated empty barns at a profit. Some burned their oats rather than sell them. The wife of one former unionist politician was paid to heat a “horse solarium”. Within seven months of the scheme’s launch, civil servants were warned that hotels were running their heating with their windows open, blasting heat into the sky. The farmers who supplied Moy Park, Northern Ireland’s biggest poultry producer, were among the biggest beneficiaries (and ministers accepted free Christmas turkeys from the firm).

Yet repeated warnings of abuse, some of them delivered direct to Foster herself, were ignored. The gravy train rolled on. By the time the scheme finally shut in March 2016, £490m had been wasted. Foster, who by then was Northern Ireland’s popular first minister, had dined out on the RHI’s supposed success. But that December the eccentric Jonathan Bell, her paranoid successor as enterprise minister, blew the whistle. In an emotional BBC interview in which he prayed on camera, Bell alleged that Foster and her advisers had ordered him to postpone the closure of the scheme. She refused to stand aside pending an investigation. Sinn Féin withdrew from power-sharing, triggering a snap election.

The defiant Foster went from Arlene to “Snarlene”, and lost unionism its majority. Set against an intensifying Brexit storm, the scandal helped to ensure that sectarian rancour once again became the defining mood of Northern Irish politics.

How was it allowed to happen? As much as devolution in Northern Ireland is celebrated at Westminster as an unmitigated force for good, the reality was anything but. “Rank dysfunctionality” is McBride’s verdict – in the circumstances, a rather measured one. The public inquiry that followed the scandal – which wrapped up in December 2018 – revealed a litany of political failings. Foster, for instance, did not even read the legislation she introduced. And at the heart of the story of why public money was allowed to burn for so long are her special advisers (spads). It was they, rather than elected ministers or civil servants, who ran the show: allegedly pressuring Bell to keep the RHI scheme open, lobbying for cost controls to be delayed, and tipping off businesses before it closed. All deny wrongdoing, and McBride has been threatened with legal action.

Yet what cannot be disputed is that Stormont was more spadocracy than democracy. Power was concentrated in the hands of unaccountable advisers who communicated in secret, on private email accounts and sometimes via Post-it notes. In some cases, Sinn Féin ministers took direction not from civil servants – who seldom said no to their political masters anyway – but shadowy ex-IRA men.

A system this defective was always bound to collapse. Arguably, what kept it going was the DUP and Sinn Féin’s shared desire for supremacy in their own communities. That sustained them in government as much as Treasury money, which, in presiding over cash for ash, they believed they were spending with no consequences. On the eve of the Good Friday Agreement, a beaming Tony Blair famously told the world’s media that he felt the hand of history upon his shoulders. McBride shows us that it found a much happier home in Whitehall’s wallet.

McBride is scrupulously fair. He stops short of the easy conclusion: that the scandal and the deeper malaise it revealed mean that devolution cannot come back. Cash for ash could, he says, be the “painful surgery” that provides impetus for necessary reform. Yet nearly three years on, it looks more like the beginning of a downward spiral from which there may be no way back.

After reading McBride’s book, whether devolution in its old form can return is not the question that arises. Instead, readers will find themselves asking whether it should. That is a dangerous place for any country to be – let alone one whose main parties dispute its right to exist.

Patrick Maguire is a political correspondent for the New Statesman

Burned: The Inside Story of the “Cash-for-Ash” Scandal and Northern Ireland’s Secretive New Elite

Sam McBride

Merrion Press, 409pp, £16.99