RHI errors that led to huge liabilities to people of the North were no one individual or organisation's fault, Inquiry finds

In the Report, the Inquiry said the RHI scheme was a “project too far” and while motivated by the laudable aim of encouraging the use of renewables rather than fossil fuels in heat production, the Northern Ireland stand-alone scheme should never have been adopted.

“The NI RHI scheme was novel, technically complex and potentially volatile, especially because of its demand-led nature and the wide range of variables - such as fluctuating fuel costs – which could affect its operation.

"These features together made the scheme highly risky, yet the risks were not sufficiently understood by all those who should have understood them within the Northern Ireland Government, either at the outset or any time during the life of the scheme.

"Without the necessary resources and capability, DETI should never have embarked on such a novel and complicated, demand-led scheme.”

Back in June 2016 the Northern Ireland Audit Office (NIAO) reported that a failure to implement spending controls in the North that had being used in RHI schemes in Great Britain had made the local scheme "potentially vulnerable to abuse".

The Auditor General Kieran Donnelly estimated the lack of controls could cost around £140m over five years.

"This scheme has had serious systemic weaknesses from the start. The fact that the Department decided not to mirror the spending controls in Great Britain has led to a very serious ongoing impact on the NI budget and the lack of controls over the funding has meant that value for money has not been achieved and facilitated spending which was potentially vulnerable to abuse.

"I am very concerned about the operation of this scheme and it is an area which I expect to return to in the very near future," he reported.

In response to these concerns the former Minister of Finance, Máirtín Ó Muilleoir launched an investigation into the scheme.

The Inquiry investigated the original design and implementation of the RHI scheme; its operation; the circumstances relating to the imposition of cost controls in late 2015, as well as the circumstances relating to the suspension of the scheme to new applicants in early 2016.

The scheme was run by the Department of Enterprise, Trade and Investment (DETI), which later became the Department for the Economy (DfE).

A total of 63 witnesses gave oral evidence to the Inquiry which sat for 114 days.

The Inquiry’s forensic investigative process considered and processed more than 1.2 million pages of evidence as well as almost 11,000 spreadsheets.

The Report was finalled published on Friday.

It declared: “Responsibility for what went wrong lay not just with one individual or group, but with a broad range of persons and organisations involved, across a variety of areas relating to the design, approval, management and administration of the NI RHI scheme throughout its life.

"Across those different areas, there was a multiplicity of errors and omissions…There were repeated missed opportunities to identify and correct, or seek to have others correct, the flaws in the scheme.

"The sad reality is that, in addition to a significant number of individual shortcomings, the very governance, management and communication systems, which in these circumstances should have provided early warning of impending problems and fail-safes against such problems, proved inadequate.”

The Comptroller and Auditor General for Northern Ireland, Mr Kieran Donnelly has agreed to monitor and, as necessary, pursue the effective implementation of the Inquiry’s recommendations.

The Report said it was the Inquiry’s hope that if the recommendations are followed, both in letter and spirit, it will be much more difficult for the types of general problems discovered in respect of the NI RHI scheme to re-occur.

The Report added: “Hopefully that will, in turn, lead to a better functioning Northern Ireland Civil Service, and provide for a much healthier devolved administration in Northern Ireland."