Renewable Heat Incentive Inquiry examining botched energy scheme
Head of NI Civil Service and ex-DETI chief David Sterling returns to inquiry
Former DETI energy boss John Mills faces inquiry questions for first time
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
Image source, EPAMr Sterling had "many's a robust discussion" with then DETI minister Arlene Foster when he headed the department.
He says he always "felt comfortable to challenge what the minister asked us to do".
Civil servants do all they can to help ministers deliver what they promise in their manifestos, he explains.
It is "unacceptable" that civil servants are having to deliver public services without ministerial direction, says Mr Sterling.
Fourteen months after Stormont collapsed, he says he's "looking forward to ministers returning".
Image source, AFPHe says that if a new devolved administration is ever formed again "we are going to have to be more honest" about what the civil service can and cannot deliver with its limited resources.
"That may lead to some difficult conversations... but we cannot afford to put our people at risk."
The auditor general has observed a "disregard for value for public money" as one of several themes running through the RHI scheme and other DETI projects that ended in failure.
Mr Scoffield asks how the public can have any confidence in the department given that the same problems have kept cropping up.
Image source, RHI InquiryMr Sterling says that the RHI debacle has caused the civil service to re-examine its workings and a "change of culture and mindset" has since taken place.
"Even though this was something which occurred within a small area of a small division of a small department... we know we have a job to do to rebuild confidence in the general public that we are capable of delivering.
He can't guaranteed that there "will never be a problem or a failing in the system again" but there is a "very clear recognition that we need to improve the quality of our leadership and management".
In his written statement to the inquiry, Northern Ireland's comptroller and auditor general (C&AG) says that major failings in the Bytel and BTI projects replicated those in the RHI scheme.
Mr Scoffield questions whether the public might be forgiven for thinking that DETI was a "serial offender" and didn't learn lessons from its past mistakes.
The witness insists that lessons were learned - he points to 140 projects taken through DETI's internal scrutiny committee between 2008 and 2015 and says that only the RHI scheme and one other presented major governance issues.
The rest, he says, delivered value for money, and the assessment that DETI is guilty of "serial failure" is therefore an "unfair" one.
Sir Patrick probes further as to whether the culture and practices within DETI had actually changed in the wake of the Bytel and BTI projects.
Image source, RHI InquiryHe wants to know whether it is possible that the energy division had been operating differently to the rest of the department.
Mr Sterling tells him that he was not aware of "excessive risk-taking and corner-cutting" by the energy division, and says that aside from the RHI scheme there he doesn't know of "any major governance failings elsewhere in the department" during his time running it.
A "certain doubt is raised" in the mind of inquiry panellist Dr Keith MacLean by the number of times that Mr Sterling has told the inquiry "that you just don't understand... why certain things happened or didn't happen" in relation to the RHI scheme.
"That doesn't suggest that everything is fully under control and happening as it should," he adds, and he's also worried about the continuing staff shortages in the civil service.
Image source, Getty ImagesMr Sterling says his lack of understanding about some issues is because he hasn't heard from everyone involved to get their side of the story.
On staff shortages, he points out that cuts to the civil service since 2014 have reduced the workforce by 18% but there's been no reduction in the workload or responsibilities.
"I cannot today give a guarantee that we are going to meet all our obligations and expectations, he adds.
He says that's been aggravated by the demands imposed by the UK's decision to leave the EU, which is a "huge burden across the service".
DETI was involved in two other projects that were dogged by management problems and later became the subjects of critical reports by the Northern Ireland Assembly's Public Accounts Committee.
One was a part-EU-funded cross-Irish border broadband scheme - the Bytel project.
The other was the Biosciences and Technology Institute (BTI), to provide biotechnology incubator facilities at Belfast City Hospital.
After the projects were criticised by MLAs, Mr Sterling wrote to his senior management team in DETI in November 2012, saying that the culture within the department had changed and he was satisfied that such mistakes wouldn't happen again.
But Mr Sterling points out that the same issues are "precisely" what were happening with the RHI scheme at "that very time".
That is a "source of deep regret", says Mr Sterling, who admits "considerable embarrassment", but he adds that other projects were well managed and delivered what they were designed to do.
A "number of other issues" have been caught by internal auditors and fraud investigators since the RHI scheme, says Mr Sterling.
A "significant" amount of issues have been "dealt with quickly, expeditiously and successfully".
He explains that civil servants have been given "very clear guidance" that "the moment anybody rings an alarm bell" it "should immediately be raised" with internal auditors.
The guidance is effectively "if in doubt, escalate", and that makes it much less likely that another RHI-style debacle could happen, he adds.
"More credence" should've been given to the concerns raised by a so-called whistleblower who tried to draw the then DETI minister Arlene Foster's attention to a major flaw in the RHI scheme, says Mr Sterling.
Janette O'Hagan (below) twice emailed the minister in 2013 and also met the three civil servants most responsible for the design and running of the initiative to tell them that it was so lucrative that claimants were producing heat just to collect cash.
But she was told by one of the officials that people simply wouldn't do such a thing.
Image source, RHI InquiryMr Sterling says there were signals there there was "merit in what she was saying".
The approach taken by civil servants to Ms O'Hagan's concerns was "at best, naive" and it has "surprised" Mr Sterling.
He says there is now a "much, much reduced likelihood" of similar concerns being dismissed in such a way.
Image source, Getty ImagesMr Scoffield asks if DETI had been "corporately prioritising drawing down funds" from the Treasury for the RHI scheme, over exercising "the usual type of caution that you would expect" when it came to spending public money.
"That's certainly a plausible explanation, replies Mr Sterling.
Mr Sterling says he was "surprised" that DETI overlooked seeking a crucial green light from Stormont's finance department to run the RHI scheme beyond March 2015.
The scheme was only given approval up until 2015, about two-and-a-half years after it opened.
But it ran on for months after that deadline passed before anyone at DETI noticed that it needed to be renewed, meaning that public money was being spent that hadn't been rubbed-stamped.
Image source, GettyMr Sterling says there should've been a "very clear marker" within DETI to ensure that it wasn't missed.
Finance officials who have appeared at the inquiry have said it isn't their responsibility to check up on which projects need to be reapproved, and it falls on the departments running those projects to ask them for it.
But Mr Sterling says that "good practice" should now be for the finance department to flag up to departments when approvals for spending schemes are expiring.
Settling in for his third appearance in just over a week, Mr Sterling cuts a relaxed figure, and he's not expected to be kept for too long today - he'll probably get away just after lunchtime.
Image source, RHI InquiryThe inquiry chair Sir Patrick Coghlin has already said that Mr Sterling has important things to be doing elsewhere... like keeping Northern Ireland's public services running.
Asking the questions is the inquiry's senior counsel David Scoffield QC.
In a remarkable turn of events yesterday, the DUP MP Ian Paisley used parliamentary privilege to accuse the RHI Inquiry chair Sir Patrick Coghlin of "putting words in the mouth" of a witness last week.
Ian Paisley accuses the RHI Inquiry chair of "putting words in the mouth of a witness"
Mr Paisley demanded a personal apology from the retired judge.
But he certainly hasn't got one this morning - Sir Patrick opens proceedings but makes no mention of Mr Paisley's remarks.
BBC News Northern Ireland
Last week when he was giving evidence, Northern Ireland's top civil servant admitted that meetings between Stormont ministers and their staff were sometimes not minuted in order to frustrate freedom of information requests.
Mr Sterling said the DUP and Sinn Féin were sensitive to criticism when they were in government and civil servants had therefore "got into the habit" of not recording all meetings.
Image source, Press EyeWhen he appeared again on Tuesday this week, he admitted personal responsibility for failings in the RHI scheme.
He said he should have asked the former enterprise minister Arlene Foster not to go ahead with the initiative in 2012, but he suggested that even if he had made that case it might not have been accepted by her.
BBC News Northern Ireland
The head of the Northern Ireland Civil Service since his appointment last summer, David Sterling has a lot on his plate, especially in the absence of ministers at Stormont.
He joined the civil service in 1978, rising up the ranks and eventually heading some Stormont departments, including the Department of Finance.
Image source, Press EyeAt the time of the set-up of the RHI scheme, he was the permanent secretary - the top civil servant - at the Department of Enterprise, Trade and Investment (DETI).
In November 2016, he appeared before a Northern Ireland Assembly inquiry to answer questions about the cash-for-ash debacle and denied trying to "duck responsibility" for his role in it.
BBC News NI's business correspondent Julian O'Neil profiled Mr Sterling last June, and you can read that here.
BBC News Northern Ireland
An independent inquiry into the RHI scandal was established in January last year by the then finance minister Máirtín Ó Muilleoir.
He ordered it in the wake of the huge public concernand what was then a developing political crisis surrounding the scheme.
The RHI Inquiry began in November and Sir Patrick Coghlin (below), a retired Court of Appeal judge, is its chair and has been given full control over how it will operate.
Image source, PacemakerIt will look at:
For more information on the RHI Inquiry,you can read our handy Q&A.
When the scale of the overspend emerged, public and political concern rocketed.
As the minister in charge of the Stormont department that set up the RHI scheme, the Democratic Unionist Party (DUP) leader Arlene Foster faced calls to resign from her role as Northern Ireland's first minister in December 2016.
Image source, PAShe resisted, and Sinn Féin's Martin McGuinness then quit as deputy first minister in protest at the DUP's handling of what had by then become a full-blown political crisis.
That move brought about the collapse of the Northern Ireland Executive. Now, more than a year on from that, Northern Ireland remains without a devolved administration.
You can find much more detail on the RHI scheme in our need-to-know guide.
The budget of the RHI scheme ran out of control because of critical flaws in the way it was set up.
Claimants could effectively earn more money the more fuel they burned because the subsidies on offer for renewable fuels were far greater than the cost of the fuels themselves.
The most recent estimate for the overspend was set at £700m, if permanent cost controls aren't introduced.
The massive overspend bill will have to be picked up by the Northern Ireland taxpayer.
The Renewable Heat Incentive scheme - or RHI for short - came to the fore of the Northern Ireland public's knowledge in late-2016... and the fallout from the scandal attached to it is still being felt in the region's politics today.
Image source, Getty ImagesThe scheme was set up by the Northern Ireland Executive in 2012, as a way of encouraging businesses to switch from using fossil fuels to renewable sources for generating their heat.
Those who signed up were offered financial incentives to buy new heating systems and the fuel to run them.
Thanks for joining us up on Stormont hill this morning for a special milestone - the 50th day of the Renewable Heat Incentive Inquiry!
How we've lasted this long we're not quite sure...
Anyway, we have a particularly interesting day ahead, with David Sterling, the head of the Northern Ireland Civil Service, returning to answer a few more questions after his two recent appearances.
Later, we'll hear from former Department of Enterprise, Trade and Investment (DETI) energy boss John Mills for the first time - he led the team running the scheme during a critical phase.
Proceedings start at 09:45, so stick with us for a full live stream and text commentary.