The DUP’s chief executive has denied attempting to delay imposing cost controls on Northern Ireland’s botched green energy scheme.
Timothy Johnston said he had no detailed knowledge about the Renewable Heat Incentive (RHI), which could have left taxpayers facing a near £500 million bill.
He gives evidence on Friday to a public inquiry into the handling of the lucrative subsidies for businesses switching to more eco-friendly fuels.
His written evidence relating to his time as special adviser to Stormont’s first minister was published on Thursday evening.
Mr Johnston wrote: “I had no involvement in the decision-making processes on the introduction of cost controls in 2015.
“I was unaware of the detail of any discussions, meetings, communications and final decisions on cost controls at the time.”
Delays to the introduction of cost controls in 2015 saw a spike in applications to the over-spending scheme at higher tariffs, which was widely believed at the time would be funded directly from London.
Mr Johnston added: “At no time did I seek to influence or encourage Timothy Cairns (a former special adviser at the Stormont department in charge of the scheme), or anyone else, to delay, soften or reduce cost controls.
“I was not in possession of any detailed knowledge about the scheme, its financing or operation at that time and had no reason to be so.”
The RHI was designed to encourage businesses to switch from burning fossil fuels to more sustainable alternatives like wood biomass.
The subsidies proved overly-lucrative, paying more than the wood pellets cost and encouraging firms to “burn to earn”.
Civil servants wanted to move quickly to impose limits on how much could be earned.
Mr Johnston said: “It would appear from the early days of this scheme that there was not a proper understanding of its financing, its administration appeared unco-ordinated, and there was not a sufficiently joined-up approach across government (and particularly from Department of Enterprise, Trade and Investment to Department of Finance and Personnel), to understand or recognise its flaws at an early stage.
“The fact the subsidy payment was greater than the cost of wood pellets was a major flaw and this imbalance was not understood until very late.”
Former enterprise minister Jonathan Bell has raised concern about the role of DUP special advisers in the handling of the RHI.
In separate written evidence, the party’s former Stormont first minister Peter Robinson said: “Within my team there was a very clear line of authority – advisers advise, ministers decide.”
He said advisers would from time to time be asked to offer advice to colleagues.
“There was no DUP party position in relation to the RHI scheme or any element of it.”