TWO former DUP special advisers were "withholding information" on serious flaws in the RHI scheme, a senior Stormont civil servant has claimed.
Andrew McCormick told the RHI inquiry that ex-party aides Andrew Crawford and Timothy Cairns understood the scale of problems but did not properly alert civil servants.
He said officials at the time had not yet grasped the extent of the issue and there was an "incredible lost opportunity" to act urgently.
As permanent secretary, Mr McCormick was the top civil servant in the Department of Enterprise, Trade and Investment (Deti) when RHI issues emerged in summer 2015 and a ministerial submission on cost controls was discussed.
Mr Cairns was special adviser (Spad) to Jonathan Bell who succeeded Arlene Foster as enterprise minister. Mr Crawford was Mrs Foster's Spad and moved with her to the finance department.
Returning to the RHI inquiry yesterday, Mr McCormick was asked about correspondence that summer in which Mr Crawford told Mr Cairns of a potential spike in applications ahead of cost controls being introduced.
Mr Crawford had also described how RHI paid poultry producers to heat empty houses.
RHI: Stormont officials discussed suspending scheme months before costs surge
Mr McCormick said it seemed "crystal clear" that Mr Crawford understood problems with the scheme at a time when Deti "hadn't grasped it".
Inquiry panellist Dame Una O'Brien asked Mr McCormick if he believed the Spads were keeping information from officials.
"Yes, that's what happened," Mr McCormick said.
He added: "To understand that, to know from the submission that we have a problem and we're trying to solve a problem and not to say, 'You don't understand your problem, here's the real understanding' – is that not straightforwardly withholding information?
"It seems very clear to me that it is withholding information that was relevant to the submission that they both had."
Mr McCormick has previously alleged that Mr Cairns told him Mr Crawford was behind a delay in introducing RHI cost controls.
Mr Crawford had a number of close relatives with boilers registered in the RHI scheme, but he denies wrongdoing.
The inquiry has previously heard from Mr Cairns who said he raised RHI concerns with senior Deti officials including Mr McCormick – and became frustrated with their lack of action.
Mr McCormick said he did not believe Mr Cairns raised such issues with him.
He recalled a conversation with Mr Crawford in which some concerns might have been raised, but said there were no specifics.
Mr McCormick said officials would have understood the issues if they were expressed in "clear terms".
"Now we have to accept and admit to a lot of things that make us look unimaginative, leaden-footed and slow-witted, but we're not completely stupid," he said.
Inquiry barrister David Scoffield suggested to Mr McCormick that unless "very clear and very specific" allegations were received by Deti, "not very much gets done".
Mr McCormick accepted there were learnings for the department "in terms of commercial awareness, sensitivity, responsiveness".
Earlier, Mr McCormick was asked about the July 2015 submission on cost controls taking two months to be signed off by Mr Bell.
Mr McCormick said there was "no good explanation for us being so passive", but he said there was a "reluctance" to have the submission cleared by Mr Cairns – who has denied any desire on his part to see the approval delayed.
"I have no hesitation in retaining the view that there was a reluctance to approve the submission," Mr McCormick said.
But he accepted officials could have bypassed the Spad to speak to the minister.
Mr McCormick will continue giving evidence to the inquiry later today.
