DETI officials were so "fixated" with trying to get more money to cover the RHI scheme's burst budget that they didn't look deeper to find out what had caused the problem, says Michael Woods.

Civil servants had a "perception" that the big issue with the RHI concerned its budget and therefore didn't tell internal auditors about the scheme's lack of spending controls, he tells the inquiry.

Image source, Getty Images

If they'd "stepped outside that problem" and tried to establish how the budget problem had occurred then a better solution could've been found, he adds.

The question of whether more public money should actually have been thrown at the scheme "didn't seem to really be at the forefront of people's thoughts".

Claire Hughes, an independent member of DETI's departmental board, had a home heating system registered on the domestic RHI scheme and a man carrying out a service on it in early-2015 told her how busy he was, the inquiry hears.

The man was heating system installer Neil Elliott, who gave evidence to the inquiry in February.

He told Ms Hughes the RHI was "open to abuse as the more fuel that was burnt the greater the return", and there were "reports of farmers heating empty sheds and churches being heated when no-one was in them".

In her written evidence to the inquiry, Ms Hughes says she told DETI officials, including Trevor Cooper who appeared as a witness yesterday, in June 2015 about what she'd heard.

Asked about that in his written evidence, Mr Cooper says it wasn't until autumn 2015 that Ms Hughes gave him the information and she wasn't prepared to put it on record.

Either way, Michael Woods says it wasn't ever drawn to his attention and he believes he should've been told that the scheme was open to abuse.

If he'd been alerted to it and the claims were found to be true he would've had "sufficient concern" to bring forward the date of the audit of the RHI.

Internal auditors were not told about a series of complaints about the flaws in the RHI scheme that were made by a woman described as a whistleblower, says Michael Woods.

Janette O'Hagan (below) first contacted the then enterprise minister Arlene Foster in August 2013 and followed up her concerns by contacting DETI time and time again until March 2015.

Image source, RHI Inquiry

Mr Woods says he's "absolutely 100% certain" that nobody in the department's energy team told him about those complaints - he first discovered them in September 2016, long after the scheme had closed.

He says he should've been told about them when they came to light - DETI's anti-fraud policy states that auditors should be consulted when such allegations are received.

Mr Woods is "99.9%" sure that if Ms O'Hagan's claims had been drawn to his attention he would've made sure the audit of the RHI was carried out sooner than had been planned.

A decision was made to formally audit the RHI scheme - it was to take place at the end of 2015 and would be a systems review.

Image source, RHI Inquiry

That's essentially a check on how the financial side of the scheme was being run - it was not an investigation into any allegation.

As Mr Woods puts it, that was "prior to anybody knowing there was a problem with the scheme".

Internal auditors were "told nothing about any problems" with the RHI scheme when questions were posed in January 2015, says Michael Woods.

While DETI's energy team that was running the RHI gave auditors some details about the initiative, it didn't mention other key factors, including the fact it had no cost controls.

Image source, RHI Inquiry

It also failed to declare that a promised review of the scheme, which had been a key condition of its original approval, had not been carried out.

Mr Woods says it surprised him that the scheme hadn't been examined by auditors long before that.

Internal auditors received information from DETI's energy team about the RHI scheme in January 2015 but it wasn't enough to reveal that "there was a fire", says Michael Woods.

The auditors were told about the nature of the scheme, the budget that had been allocated to it and the fact that it was being administered by an external body, Ofgem.

Image source, Getty Images

Mr Woods says the information he was given showed him there were "risk factors there" and there was "something that needed to be looked at".

The scheme had been open since November 2012 but hadn't been reviewed by auditors and Mr Woods says there was an "obvious gap in the audit coverage.

Given that the RHI scheme was "a completely novel scheme... based on demand", inquiry chair Sir Patrick Coghlin asks what information was available to auditors to identify that it carried risks.

Michael Woods says that when he joined DETI in 2014 "there was no information in terms of the audit strategy, nor the audit plan, nor in the departmental risk register".

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Sir Patrick puts it to the witness that there was no system in place to draw this "risky, volatile unpredictable scheme" to the audit team's attention.

"That is my understanding," says Mr Woods.

There has to be "trust... openness and transparency" between internal auditors and permenant secretaries - the top civil servants - in Stormont departments, says Michael Woods.

"I have to have complete right of access to [the permanent secretary] so I can bring matters of concern to him," he adds.

During the time the inquiry is covering, the permanent secretary that Mr Woods worked with was Dr Andrew McCormick (above), who has given extensive evidence to the inquiry, most recently last week.

Mr Woods says he and Dr McCormick had a good working relationship and was allowed the necessary degree of openness and freedom of access.

Some civil servants view internal auditors as a "necessary evil" because "nobody likes being asked questions", says Michael Woods.

Inquiry counsel Donal Lunny (below) asks him if auditors are seen as a "thorn in the side" or a "vital critical friend" to senior officials.

Image source, RHI Inquiry

Mr Woods says in his experience his audit team is considered to be an "additional pair of eyes" and people who officials can go to for advice.

Internal audit has two functions, he explains - systems audit reviews consider the risk controls in place on a scheme or function, while investigations consider allegations that have been made about how schemes and projects operate.

After taking the oath, Michael Woods settles into the witness chair in the Senate chamber.

He's the head of internal audit at the Department for the Economy, which was known as the Department for Enterprise, Trade and Investment (DETI) during the life of the RHI scheme.

Mr Woods has been a civil servant for 33 years this month and his roles in that time have included heading the internal audit team at the Department for Social Development before he took up the same post at DETI in August 2014.

If you're keen enough to read it, you'll find his witness statement on the inquiry's website, external.

BBC News NI

Stormont civil servants failed to make sure that adequate checks were done to guarantee spending controls were in place in the RHI scheme, the inquiry heard.

Image source, Pacemaker

An internal scrutiny panel signed off the RHI in 2011 after taking a colleague's word that spending could be stopped if the initiative went beyond its budget.

But that assurance was not correct and inquiry chair Sir Patrick Coghlin said the civil servants who sat on the scrutiny panel would have found that out for themselves if they had read the scheme's rules.

BBC News NI

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 concern and what was then a major political crisis surrounding the scheme.

The RHI Inquiry began in November last year 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, Pacemaker

It is looking at:

• the design and introduction of the RHI scheme
• the scheme's initial operation, administration, promotion and supervision
• the introduction of revised subsidies and a usage cap for new scheme claimants in autumn 2015
• the scheme's closure in February 2016

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, PA

She 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, well beyond a year-and-a-half 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 the initiative 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.

At one point the estimate for the overspend was set at £700m if permanent cost controls weren't introduced - temporary cuts have since pulled the budget back on track for now.

Whatever the scale of the bill, it 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.

The fallout from the scandal attached to it is still being felt in the region's politics today.

Image source, Getty Images

The 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.

We've got that Friday feeling up on the hill at Stormont as this week at the Renewable Heat Incentive Inquiry draws to an end.

Today could be particularly interesting as we hear from the comptroller and auditor general Kieran Donnelly, whose Northern Ireland Audit Office issued a brutal report about the RHI scheme in July 2016.

Image source, PA

First up in the witness chair will be the Department for the Economy's head of internal audit Michael Woods.

The session starts shortly - watch our live stream and follow our text commentary throughout the day.