Renewable Heat Incentive Inquiry examining botched energy scheme
Former DETI energy boss John Mills returns to answer inquiry questions
Inquiry set up after public concern over scheme's huge projected overspend
Retired Court of Appeal judge Sir Patrick Coghlin chairing inquiry at Stormont
Public evidence sessions expected to last until well into 2018
Even though the afternoon session was extended the inquiry still has more questions for Mr Mills - he'll return at a later date.
So that's it for today. We'll be back tomorrow to hear from the head of the RHI scheme administrator Ofgem, so join us from 09:45.
Have a wonderful evening out in the sunshine!
BBC News NI
A former head the team that was running the RHI scheme revealed he commissioned a vital document that outlined potential concerns with the initiative but didn't read it when it was produced.
John Mills claims he asked one of his civil servants Peter Hutchinson to put together a handover note before he moved to another job.
Image source, Getty ImagesThe handover outlined the work that had to be done on the scheme and included "immediate actions" that Mr Hutchinson felt had to be addressed.
It also referenced correspondence from Janette O'Hagan, who had been emailing to bring the flaws of the scheme to the department's attention.
Mr Mills told the inquiry he can't remember seeing the handover or reading it and assumed that staff working in his team flag up any serious issues contained in it.
While Mr Mills is not making excuses for not acting on Ms O'Hagan's emails, he explains that often DETI receives emails criticising its policies.
Usually, he says, they never end up as a whistleblower or fraud case.
Image source, RHI InquirySir Patrick says that kind of correspondence should have been taken seriously by the department's leadership at some stage given that "this woman was repeating herself for 18 months".
"It seems the system has been a total failure, as far as [Ms O'Hagan] is concerned."
Image source, RHI InquiryDame Una O'Brien has a simple, direct question about why the whistleblower's concerns about were not acted upon: "Where in your view does the buck stop?"
"Successive people didn't pick up on Mrs O'Hagan, including in my time," he admits.
"It's hard to say why that came about."
In March 2015, Ms O'Hagan emailed DETI again, saying she hadn't seen since her last correspondence that suggested the department was doing anything to address her concerns with the RHI scheme.
She argued again that as a result of the scheme people were wasting heat to earn a profit.
Image source, Getty ImagesMr Mills was says he was unaware of that email but says it it should have been brought to his attention because Ms O'Hagan had been so persistent.
"She was right all along," he adds.
The so-called whistleblower Janette O'Hagan (below), who tried to draw the then DETI minister Arlene Foster's attention to a key flaw in the RHI scheme in 2013, contacted the department in May and June 2014 to follow up on the concerns she'd raised.
Mr Mills was copied into the June email chain by a member of DETI staff but he says he wouldn't have read it.
Image source, RHI Inquiry"There were a lot of emails and pieces of correspondence and I wouldn’t have had time to look at individual cases," says Mr Mills.
One of the civil servants working on the scheme replied to Ms O'Hagan, telling her that the department intended to "review elements" of the scheme and adding that "the issues you've raised are on our radar".
Ms O'Hagan told the inquiry that she took comfort from what she'd heard from DETI.
The RHI scheme required approval from Stormont's finance department and that was granted until March 2015.
That scheme had to be reapproved at that point but it didn't happen and for two months DETI was continuing to accept applications and spend money through without the authority to do so.
Image source, Getty ImagesMr Mills says he became aware in May 2015 that the approval had expired.
He'd been told about the need for re-approval the previous year when he joined the department, but admits he forgot about it and hadn't written it down.
DETI told the Northern Ireland Assembly's Enterprise Committee in spring 2014 that the uptake on the RHI scheme was "comparing favourably" with the the performance of the similar initiative in Great Britain.
It was also anticipated that it could "experience a higher volume of applications" than the GB scheme.
Image source, Getty ImagesMr Scoffield says that "undermines" the suggestion that Mr Mills has made that the scheme was under performing and there was no need to worry that the scheme might end up "running away with itself".
The witness accepts this and admits that he was guilty of "blinkering".
Mr Mills says his beliefs were based on the knowledge that DETI was handing money set aside for the scheme back to the Treasury.
Mr Hutchinson's point in his handover that a potential problem with the subsidies on offer in the RHI scheme should be addressed "as a matter of urgency" should have been acted on, says Sir Patrick.
He acknowledges that doing so would've resulted in a "potential delay" to opening the domestic RHI scheme.
Image source, Getty ImagesBut he says officials should've been aware that the risk of not dealing with the issue was "serious enough" for them to consider pausing the work on the domestic scheme until it was sorted out.
"It just didn't happen," he sighs.
Dr MacLean comments on the approach Mr Mills took to decision making.
"I’m not seeing how any of the approach you’re describing to us would lead to an evidence-based set of decisions being made about current, or emerging priorities," he says.
Sir Patrick chimes in, criticising the focus the department had on the domestic scheme, while the non-domestic scheme's cost controls were left hanging.
He says: "What happened on the ground was a complete and utter focus on the cost of the domestic scheme on everything else. That cannot be a good way for any department to conduct itself."
Image source, RHI InquiryMr Mills says he must accept that his views and focus at the time about the scheme were wrong.
"The scheme was under-performing and really the budget was the driver. We needed to use that Treasury money," says Mr Mills.
"Those are the things I had in my head. Those things were influenced by what came before me. They’re not the right views."
Mr Mills says the department should have focused entirely on cost controls instead of the domestic scheme.
But Sir Patrick retorts that the question is not about one focus: "It's about being alert."
The subsidies on offer through the RHI scheme "can become overgenerous", wrote Mr Hutchinson in his May 2014 handover note.
He explained that by adding a mechanism called tiering to the scheme would be a solution to that - it would allow the subsidy rates to be dropped whenever a claimant had used their heating system for a certain length of time, therefore stopping the incentive to burn fuel simply to earn money.
Image source, Getty ImagesMr Hutchinson wrote twice that tiering should be considered "as a matter of urgency" - it was the only issue mentioned in the handover that he suggested was in need of such immediate attention.
Asked what he would've expected his new staff to do after they'd read that point, Mr Mills says that it "should have been escalated" to him.
It would've taken "a week or two" for the new staff who began working on the RHI scheme in the summer of 2014 to complete the suggested background reading about the initiative, says Mr Mills.
In his handover note, Mr Hutchinson provided a reading list for his successors that he felt would give them a good grasp of the responsibilities.
Image source, Getty Images"If you were reading it to become familiar with it you'd have to stop every third sentence to look something up... so it would take a while if you were truly absorbing it," says Mr Mills.
He again makes the point that time was at a premium for those working on the scheme.
Mr Scoffield turns to the "fairly lengthy list" of action points Peter Hutchinson included in his handover note.
Mr Mills has already said he didn't read the note - or at least not in any detail.
The list includes "immediate actions" that should be undertaken by August 2014.
As several witnesses have already noted, it's questionable whether such a comprehensive list could be fulfilled in the time envisaged.
The points include a reference to a review of biomass tariffs under 100kW, and to "consider tiered tariffs to prevent over-payments".
Mr Scoffield asks the witness how much of this he would have understood, if he'd read the note.
"I wouldn't have understood what tiering was," he says.
Inquiry panel member Dame Una O'Brien suggests that it appears Mr Mills was "without interest or curiosity" about the RHI scheme in 2014.
She points out that he told the inquiry his first meeting with the team running the RHI scheme was about two months after he began his role as DETI's energy boss.
Image source, Getty Images"That lack of contact with the team and what sounds to me like a lack of interest... in what they were doing... - if that's an unreasonable picture I'm giving you a chance to fill in the gaps," she tells him.
Mr Mills says he rejects the suggestion he wasn't interested and compared the workload in his role as having been "like keeping a series of spinning plates going".
"Other issues appeared to be in greatest risk of tumbling off... and resulting in risk," he adds.
He says that the RHI scheme "did not appear to be a high-risk area" when he joined the department and therefore he did not get deeply involved with it.
Image source, Getty ImagesMr Mills says it's unlikely he would have discussed the RHI scheme handover note with the new staff who started working on the scheme in the summer of 2014.
Inquiry barrister Mr Scoffield says it appears that after commissioning the note from Mr Hutchinson, Mr Mills doesn't appear to have done anything to make sure the "important information" in it was picked up and acted on by those succeeded him.
"OK, fair enough," accepts Mr Mills.
Mr Mills told the inquiry before lunch that he had asked Peter Hutchinson to supply a handover note.
Mr Scoffield quotes from Mr Hutchinson's witness session in which he said he couldn't recall talking with Mr Mils about continuity.
"I clearly recall asking him to do that (write the note)," Mr Mills says.
Image source, RHI inquiryWhen asked by Mr Scoffield whether Mr Hutchinson told him he had written the handover note, Mr Mills say he did.
"And I said - great, well done," he adds.
That brings the day's opening session to an end and we're off for a dander round the sun-kissed Stormont estate.
Join us again when the inquiry resumes at 14:00.
Mr Mills told the inquiry a short time ago that he can't remember seeing or reading the RHI scheme handover note that he had asked Mr Hutchinson to draw up.
Mr Scoffield asks why he felt he wasn't expected to go through it in detail - was it because it contained a level of detail he wasn't expected to be across or simply due to a lack of time?
Image source, Getty ImagesMr Mills says time would've been an issue and he didn't have enough of that to assess wot that was "down a couple of levels" within his team - instead, he was dealing with higher-level issues.
He reminds the inquiry that he had insisted on the handover note being prepared and on the appointment on a temporary member of staff, Davina McCay, to act as a "bridge" until new staff arrived work on the RHI scheme.
Mr Scoffield dissects a series of communications between Ms McCutcheon and Mr Mills.
On more than one occasion, Ms McCutcheon brought up how important Mr Hutchinson was to the RHI scheme.
Image source, RHI InquiryWhen he applied for another role in the civil service, she suggested that Mr Mills should give him a temporary promotion within DETI but Mr Mills felt that was not appropriate.
In response, Mr Mills says that he had failed to realise at the time how vital Mr Hutchinson was to the RHI scheme.
"What wasn’t said that if you let Peter go there will be a disaster and the non-domestic scheme will run off the tracks," says Mr Mills.
Before leaving DETI, Mr Hutchinson put together a handover note, outlining the work that had to be done on the RHI scheme. This note includes "immediate actions" that he felt had to be addressed like looking at one of the key flaws.
Mr Mills had asked Mr Hutchinson to draw the document up but he can't remember seeing it or reading it.
Image source, GettyHe argues that "if you really think there's a crisis and the train's running off the rails, a train running off the rails, a handover is not the vehicle to put that sort of stuff in".
It should instead be flagged in risk register, he claims.
But Dr MacLean makes the point that the note wasn't looked at by the people working on the scheme.