That was one of the most intriguing days at the RHI Inquiry to date, we think - have a read through the posts below to find out what two key figures think of some civil servants' ability to properly handle public money.

Spoiler - it's not great.

Just one week of hearings to go but what a week it promises to be, with star witnesses including former DUP and Sinn Féin ministers, the head of the civil service and his predecessor.

Join us again on Tuesday morning at 09:45 - have a great weekend!

BBC News NI

The top auditor in Stormont's enterprise department said his investigation into the RHI scheme led to him producing the most damning of the 500 reports he has done in his career.

Michael Woods deemed that the risk management in place for the initiative was "unacceptable".

Image source, Pacemaker

He could not recall a time when the oversight of a scheme or project had been as bad.

He found a raft of governance problems and he told the inquiry: "This is the worst opinion I have ever had to give."

Conor Macauley
BBC News NI environment correspondent

Kieran Donnelly "anticipated a hostile reaction" from the economy department to his Audit Office report about the RHI scheme in summer 2016, external, he admits.

But to his "great surprise" he found the opposite and there was no defensive attitude from the department's leadership.

Image source, RHI Inquiry

The Audit Office wasn't hindered by the officials when it was examining the scheme - that's something of a contrast to the experience of the department's internal auditors when they were looking at it in 2015, as the inquiry heard today from Michael Woods.

Mr Donnelly says his RHI report was "important to get out publicly" and his team "moved very quickly" to publish it.

"It was probably one of the fastest reports we ever produced and we couldn't have done that without the cooperation with the top of the department."

There's "no immediate prospect" of the auditor general lifting his qualification of the accounts of Stormont's economy department, he says.

It remains in place on two grounds. They are:

• The irregular spend resulting from DETI's failure to obtain reapproval for the scheme in March 2015
• The insufficient assurance about controls to prevent and detect abuse of the scheme

Dame Una O'Brien notes that the Audit Office report of June 2018 refers to "ongoing weaknesses in controls" and Mr Donnelly says the "jury is out" on what the Department for the Economy has put in place.

"One of the factors behind that is the inspection regime for boilers has been quite slow to get off the ground," he adds.

The Northern Ireland Audit Office has lost 30 staff in the past five years due to budget cuts, says Kieran Donnelly.

It now operates with 110 staff and he says he needs resources to enable his office to carry out its vital function given that it has to "keep an eye" on how £25bn of public money is spent.

"We've taken our pain in terms of austerity," he says.

A whistleblower gave a letter to the then first minister Arlene Foster in January 2016, detailing concerns about how the RHI scheme had been "seriously abused" and giving examples of how empty sheds were being heated in order to generate more subsidies.

It was passed to the Northern Ireland Audit Office and Kieran Donnelly says that when he saw it his "first instinct" was that it "looks like fraud".

Image source, PA

But when he looked at the scheme's rules, he found they were "very, very loose" and concluded that something needed to be done about their "deficiencies".

"There's absolutely no doubt about it - a lot of what was going on might've been compliant with the letter of the scheme but was driving coach and horses through the purpose and spirit of the scheme."

Parts of the Northern Ireland Civil Service are "very proud" of meeting targets but to do so they take a lot of "shortcuts", says Kieran Donnelly.

The RHI scheme was set up with the objective of helping Northern Ireland to increase its use of renewable energy sources in the production of heat and it certainly did that.

Image source, Getty Images

But the auditor general says "it's all very fine meeting renewable targets but you also have to look at how you do it" and "great, great care needs to be taken" when working that out.

So, while the RHI had a big hand in achieving the renewable energy use target, one of its "perverse consequences" was that it "put more carbon into the atmosphere", explains Mr Donnelly.

Sir Patrick Coghlin agrees, saying that "if you're not doing it properly you're not delivering it".

Even if you've only taken a passing interest in the RHI Inquiry, you'll have noticed that the lack of note-taking at meetings has been a recurrent mantra.

Senior civil servants have told the inquiry that minutes were not taken for fear they could be leaked or released to the public under freedom of information legislation.

Image source, RHI Inquiry

Kieran Donnelly says the civil service needs to get back to basic standards of public administration - there are "a lot of simple, practical things here that can be tightened up".

"This is something the civil service was traditionally good at - keeping the public record," he says.

When he finds that a key decision has not been documented he does "get very annoyed and I'll make a big deal of it".

There needs to be a complete change in how Stormont's economy department allocates staff to specialist, complex areas of work, advises Kieran Donnelly.

He says that instead of moving existing generalist officials into specialist roles, it may have to look elsewhere to bring in talent from the private sector.

Image source, Getty Images

"You might have to pay more in the market but wouldn't that be much better in the long run than having another saga like RHI?"

The civil service "simply cannot afford not to get the best people" for the job.

The Northern Ireland Civil Service has a "very closed culture" and it's going to be a "big job" to change that, according to Kieran Donnelly.

Teams within departments need to work together much more and there also needs to be better communication between departments, he tells the inquiry.

Had there been a "culture of openness", big problems with the RHI scheme could've been addressed much sooner.

It would take a "very special type of leadership" and a "massive change in behaviours" to change the culture.

Sir Patrick Coghlin raises three questions that might give a clue about what his final report will contain.

Image source, RHI Inquiry

They are:

• Should there there be education for civil servants in commercial concepts and value for money?
• With high-risk, big-money schemes like the RHI, should external experts be called in or experts be found within the civil service?
• Where was the sharing of knowledge between Stormont departments and other public bodies about what was happening with the RHI?

Every public official should "treat taxpayers' money exactly the same as they would treat their own money", says Kieran Donnelly.

He's "listened a lot" to the hundred-odd days of evidence at the RHI Inquiry - we trust he's been following it here on the BBC.

Image source, RHI Inquiry

From what he's seen, it's "clear to me that value for money isn't front and centre in the minds of just too many civil servants".

That "needs to be ingrained in the minds of a whole generation" of officials, he says.

There's a "huge dichotomy" between the principles the civil service claims to adhere to and "what's actually going on day to day" in Stormont departments.

As the comptroller and auditor general, Kieran Donnelly heads the Northern Ireland Audit Office.

It is independent of government and its role is to examine how effectively and efficiently any public entity is carrying out its activities and to check that public money is spent in the proper way.

"Essentially we're a one-stop audit shop for the entire public sector so I audit the accounts of practically all public bodies in Northern Ireland," explains Mr Donnelly.

Image source, RHI Inquiry

He published a damning report about the RHI scheme in July 2016 - it revealed that "serious systematic failings" meant it was likely to hit the Northern Ireland budget by "hundreds of millions of pounds" - and you can read that report in full here, external.

Mr Donnelly makes his affirmation to tell the truth to the inquiry and you'll find his witness statement in two parts here, external and here, external.

The RHI fiasco has clearly demonstrated that some civil servants don't have even a basic knowledge about the proper way to do their work, says Michael Woods.

He sometimes feels officials "don't understand" simple principles about spending public money and there needs to be a "constant reeducation" on those points.

In his written evidence, he gives a savage criticism of the officials who worked on the RHI - Stuart Wightman, Seamus Hughes and John Mills.

In not providing him with emails from whistleblower Janette O'Hagan they'd been guilty of a "failure to act in line with... openness, objectivity, honesty and leadership".

He tells the inquiry that their level of cooperation with auditors was "one of the lowest" he's ever experienced.

A handover note about the RHI scheme that was prepared by a DETI official should have been drawn to the attention of internal auditors on day one of their examination, says Michael Woods.

Peter Hutchinson, who'd almost single-handedly worked on the scheme's original design and initial implementation, had drawn up the detailed document before he left the department in late-spring 2014.

It outlined urgent issues that he believed his successors would have to address.

But in response to questions from the auditors, the staff who'd received it said some of the scheme's problems had arisen because important knowledge about the RHI had been lost during the turnover of staff.

Image source, Getty Images

As a result, one of Mr Woods' recommendations in his audit report was that the loss of knowledge that occurred when officials changed jobs should be tackled.

What he didn't know when he was writing his report was that there had been a handover note - the officials didn't mention it or give it to him during his audit.

It finally emerged in December 2016, when RHI team member Seamus Hughes pulled a copy from his desk drawer - Mr Woods was surprised to learn of its existence.

"There was no attempt to say: 'By the way, we have this document, which tells us lots and lots of interesting stuff about the scheme'," he says.

If he'd been told about it at the start of his audit it "would've saved me a significant amount of time".

In his audit report, Michael Woods concluded that the risk management for the RHI scheme was "unacceptable" - that's the worst review it's possible to give.

He's spent 10 years as a civil service audit boss and has carried out about 500 reviews like the one he did of the RHI.

Image source, RHI Inquiry

He can't recall ever having dealt with something "that bad" and it's "absolutely... the worst opinion I've ever had to give".

He discovered a raft of shortcomings, including that the officials running the scheme had no understanding of how its budget worked and no understanding of their responsibilities on how it was to be monitored.

He made recommendations for urgent action on seven points but he says he could've made many more if he'd had to dig even deeper.

From the outset of the RHI scheme, there had been a plan to set up an oversight board, made up of officials from DETI and the initiative's administrator Ofgem, but it never happened.

The internal auditors didn't know that and asked the RHI team how often the board met and whether its meetings were documented.

Image source, RHI Inquiry

The response was: "Don't know - DETI has received no information around such meetings."

It astonished Mr Woods and he can't help but laugh when he says: "I have never seen a response like that from somebody to an audit question."

"It's pretty stark," says surprised panel member Dame Una O'Brien.

DETI's internal auditors didn't feel the officials who were in charge of the RHI scheme were able to answer basic questions about it, says Michael Woods.

"To say I was frustrated during that audit would be an understatement," he adds.

Among the simple things the auditors wanted was an explanation about how the scheme was offering value for money and how the department could monitor what the scheme administrator Ofgem was doing.

Image source, Getty Images

"They didn't address the issues - they didn't seem to understand where I was coming from.

"They'd been in post nearly two years - they should've understood enough about the scheme to answer my questions."

It "shocked" Mr Woods when the civil servants directed his auditors to officials who'd long since left the department for answers to some of the questions.

He'd "never, ever encountered that in any audit I've ever done before".

A "sense of jeopardy" about the RHI scheme "increased" when DETI's audit committee was told about issues with the initiative's design and control and December 2015, according to Michael Woods.

Those concerns were what triggered the auditors to decide to examine the scheme at the earliest possible opportunity.

It was only once the audit had commenced that Mr Woods became aware there was no way to suspend or stop the scheme.

"What were the controls to prevent or detect the risk? There were no controls to do either and I think that had been pretty obvious when we started looking at it."