Mrs Dolan didn't realise "how novel or complex" the RHI scheme potentially was when she first became aware of it, she says.

She met DETI's energy boss Fiona Hepper in August 2011 to dicsuss it for the first time, with Mrs Hepper seeking input from the auditors on the new initiative, which was high priority for the division.

In her written witness statement, Mrs Dolan said the project would also have been high priority for audit "because of the budget and because it was new".

For that reason, the audit team offered to provide advice and guidance and Mrs Dolan says it was left to the energy team to approach the auditors when they needed it.

DETI's audit team considered financial risks using corporate and divisional risk registers rather than lower-level project risk registers.

Mrs Dolan says she would have worked on the basis that any significant issues arising in the project register "should be escalated to divisional level".

The inquiry has already heard that once the risk register for the RHI scheme was drawn up it was effectively left on the shelf and never updated.

Image source, Getty Images

Mrs Dolan explains that risk registers for individual projects like the RHI scheme "should be reviewed regularly" and inquiry chair Sir Patrick Coghlin comments: "Yes. But it wasn't."

The auditors relied on civil servants to note the key risks involved in the projects they were working on, says Mrs Dolan.

"You're reliant on the individuals in the business area identifying a risk, prioritising it accurately and knowing then to escalate it up to the next level," she explains.

The Northern Ireland Audit Office (NIAO) raised concerns that there was a "lack of internal audit coverage" at DETI in 2011-12.

Giving the background to that finding, Mrs Dolan explains that audits "weren't taking place in accordance with our schedule" and some slipped into the next financial year and needed to be caught up on.

Image source, Getty Images

Asked how serious a finding it was by the NIAO, Mrs Dolan says it became a high priority and was "taken quite seriously" and closely monitored.

She says the audit team caught up on the backlog in the last quarter of 2013.

Mrs Dolan explains that her team was "stretched", adding: "We did have resource difficulties during that period."

After taking the oath, Elaine Dolan takes her seat and she's being questioned by the inquiry's senior counsel David Scoffield QC.

You can read her written witness statement to the inquiry here., external

Image source, RHI Inquiry

She started her career at the professional services firm KPMG in 2001 and joined the civil service as DETI's head of internal audit in May 2010.

She held that role until August 2014 when she took a career break and returned to work in January last year in a new post heading the higher education strategy management office at Stormont's Department for the Economy, formerly DETI.

BBC News NI

Poultry firm Moy Park was told of proposed changes in the RHI scheme before they had been cleared by senior DETI officials or the minister, the inquiry was been told.

It happened in early 2015 as pressure in the scheme was starting to build but before officials realised.

Moy Park was one of the biggest users of the initiative as more of its producers made the switch to biomass heating systems.

It told officials another 200 chicken houses were likely to apply that year.

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 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, Pacemaker

It will look 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 2015
• the scheme's closure

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, 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 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.

Welcome to Wednesday's live coverage of the Renewable Heat Incentive Inquiry - it's day 61 and we've a new member for the ever-expanding cast of characters.

Elaine Dolan was was the head of internal audit at the Department of Enterprise, Trade and Investment (DETI) between 2010 and 2014.

We'll be hearing from her when proceedings start shortly, and yesterday's witness Seamus Hughes, another DETI staffer, will return this afternoon.