Stephen Brimstone accepts that a conflict of interest arose when he was involved in a discussion with other DUP ministerial advisers about the RHI scheme in the summer of 2015.

By that stage, he'd ordered a biomass boiler through the scheme and therefore had an interest in the RHI.

He spoke to Tim Cairns and Dr Andrew Crawford about the emerging problems with the initiative and the urgent need to add cost controls to it.

Image source, RHI Inquiry

Mr Cairns, who was advising the then enterprise minister Jonathan Bell, sent Mr Brimstone a confidential document about the issues facing the scheme.

The witness believes he was "trying to be helpful" and claims he didn't realise there was a potential conflict.

Asked why he didn't see that, he says he's "asked myself that question so many times", adding that he'd usually be "pedantic" when it came to checking such issues.

Ofgem told the PSNI last year that Stephen Brimstone's use of heat under the rules of the RHI scheme was "legitimate" and it was "appropriate" for him to receive subsidies.

It said money was not available for boilers that generate "heat solely for the use of one domestic premises" but "mixed uses" were eligible under the rules - for example, "between one domestic premises and another premises" - and Mr Brimstone fell into that category.

Image source, RHI Inquiry

Ofgem also concluded that even if Mr Brimstone had allowed another farmer to keep sheep in his shed for just one day it would still be considered acceptable under the rules.

Inquiry panellist Dame Una O'Brien says that "seems a long way" from what had been intended when the scheme was first drawn up.

She says that anyone in Northern Ireland could claim they were self-employed and worked in their garage for two or three days a year to qualify for the scheme.

It "absolutely" came as a shock to Stephen Brimstone in late January 2017 that his registration on the RHI scheme had been investigated by police, he says.

The Irish News obtained communication from the PSNI, external, in which a detective said that "no crime has been committed".

Image source, RHI Inquiry

Mr Brimstone's biomass boiler - situated in the shed above - was inspected for a second time in March last year and the auditor observed that there was evidence that sheep and lambs had been kept in the shed.

Ofgem asked follow-up questions, as it had done after the first inspection, and after Mr Brimstone answered them the administrator confirmed that he was entitled to be on the scheme.

Asked if he thought that would be the end of it, he says he'd "probably given up" wondering when the issue would reach a conclusion.

Stephen Brimstone says his understanding of the RHI scheme was that it was designed allow people in homes "in towns and cities and the countryside" to avail of it.

"That was primarily what you were doing though," says inquiry panellist Dr Keith MacLean - so why didn't he sign up to the similar scheme for domestic users instead?

"My view was that I couldn't heat my shed on the domestic scheme," says the witness.

Sir Patrick Coghlin suggests that he could have made separate applications under the two schemes.

Stephen Brimstone was just about to speak at a church meeting when he heard that Jim Allister made allegations against him in the Northern Ireland Assembly about his links to the RHI scheme.

"I couldn't do anything about it," says the witness.

The TUV MLA raised the issue of Mr Brimstone's biomass boiler in the chamber in January 2017 during a debate about the scheme.

Image source, Pacemaker

He said it was "scandalous" that someone could purport to qualify for the non-domestic scheme but use most of the heat for their own house.

He said Mr Brimstone already had a biomass boiler but took it out and replaced it with another one to qualify for the RHI scheme

"That's the sort of rip-off that brings disrepute to all of the scheme," said Mr Allister.

It's worth noting Mr Brimstone told the inquiry yesterday that he replaced the original boiler because of the amount of maintenance it required.

The BBC's Nolan Show also asked Stephen Brimstone if anyone in his family had benefitted from the RHI scheme.

He drafted an answer, saying that he was receiving subsidies from the scheme and his installation was compliant with the rules.

He passed that to the senior DUP adviser Timothy Johnston with the note: "Let me know if you are content."

Image source, RHI Inquiry

Mr Johnston's reply was: "Yes, good to go."

Sir Patrick Coghlin wants to know why the witness wanted to "make sure" that Mr Johnston was content.

"In making him content, you were answering this question in this untransparent way - a limited way."

Inquiry chair Sir Patrick Coghlin accuses Stephen Brimstone of giving a "highly misleading" answer to the BBC to a question in December 2016 about a heated meeting between Arlene Foster and Jonathan Bell.

Mr Brimstone was asked by the BBC's Nolan Show if he'd witnessed the confrontation about the RHI scheme between the two ministers in February 2016.

Mr Bell told the inquiry he argued "as passionately as I could" for the scheme's closure during the meeting but Mrs Foster was "highly agitated and angry".

The DUP leader told the inquiry on Tuesday at Mr Bell "stood with his chest pushed out and was shouting".

Image source, RHI Inquiry

Mr Bell alleged that Mr Brimstone was there - the witness tells the inquiry he remembers an "angry" meeting but it was not about the RHI scheme and instead was about a trade mission to Canada that Mr Bell had just returned from.

But in his answer to the BBC in December 2016, he said he "did not witness any such exchange" between the two former ministers.

He's quizzed about it by Sir Patrick, who says the answer given to the BBC was "highly misleading if what you say now is true".

The chair says he finds "great difficulty" in understanding why Mr Brimstone could not answer a "very important" question "properly".

Mr Brimstone says he didn't feel the BBC "needed to know about any other matters that were being discussed at that meeting" and insists he answered the question "accurately".

Stephen Brimstone resigned as a DUP ministerial adviser in mid-November 2016 and the party leader Arlene Foster said at the time that it had nothing to do with his link to the RHI scheme.

Mr Brimstone tells the inquiry the same, adding that he'd originally planned to leave after the Northern Ireland Assembly election the previous May but agreed to stay on for a short while.

"I'd made plans to move on to do other things" he says.

Emails between two senior DUP advisers show that the party had received information about Mr Brimstone's involvement in the RHI scheme in October 2016.

Image source, Getty Images

Timothy Johnston wrote to Richard Bullick that a colleague had "possession of more material about SB and his RHI application".

"We are both of the view that this is not good," he added. "Now involves the auditor general and will not end well."

Mr Bullick replied: "Oh dear."

Asked whether a suggestion was ever made to him that he may have to quit, Mr Brimstone says his colleagues already knew of his plans to leave.

The Traditional Unionist Voice MLA Jim Allister received an anonymous note about Stephen Brimstone's RHI boiler in October 2016.

He's told the inquiry he regarded it as his "public duty" to pass it to the PSNI and the Northern Ireland Audit Office.

The complainant wrote that he or she was issuing the complaint with "anger and resentment", telling Mr Allister that Mr Brimstone was "defrauding the taxpayer by claiming business RHI payments".

"Little wonder the scheme is over budget with the first minister's [adviser] fraudulently claiming money he's not entitled to and living at a comfortable 24C."

An official in the Audit Office passed the note to the top civil servant in Stormont's economy department with a request to investigate it and "report back to us on the results".

Joseph Aiken suggests that the complainant was not someone on Mr Brimstone's "Christmas card list" and the witness says they "can't have been a regular visitor" to his home.

After the May 2016 complaint, Stephen Brimstone's RHI scheme boiler was inspected at the end of the next month.

On the front page of the auditor's report, it states that there was "no evidence" that the building in which the boiler was situated was being used "as a workshop or for animal pens", as had been claimed on the application form for the scheme.

The shed had the "appearance of a large domestic garage" and was "in the grounds of a house" - inside was a tractor, fence posts and tools but also children's toys and the auditor noted "no sign of animals having been there".

Image source, RHI Inquiry

But in contrast to the front page of the report, it stated in the body that there was "limited evidence" of the building being used as Mr Brimstone had claimed.

There were two versions of the audit report on Mr Brimstone's boiler - the first stated that his installation was "satisfactory" under the scheme's rules, while the second declared it to be "weak".

Ofgem asked Mr Brimstone some follow-up questions and after his answers to those the administrator told him it was "satisfied that your installation is now compliant".

A second complaint about Stephen Brimstone's RHI scheme boiler was made in October 2016.

It was sent to the Police Service of Northern Ireland (PSNI), the Northern Ireland Office, Ofgem and Stormont's Department for the Economy, which was running the scheme.

Image source, RHI Inquiry

Joseph Aiken (above) says it was followed by discussions between Mr Brimstone and fellow DUP advisers John Robinson and Timothy Johnston - the inquiry will come to those later.

The witness says he became aware of the first complaint in October 2016 but didn't hear about the second "until Monday this week".

An anonymous complainant alleged that Stephen Brimstone was involved in a "total fraud" in claiming from RHI scheme, explains the inquiry counsel Joseph Aiken.

That complaint was sent to the scheme's administrator Ofgem in May 2016 - at the time Mr Brimstone was a DUP adviser to the then first minister Arlene Foster.

It stated that the agricultural shed in which Mr Brimstone's biomass boiler was situated was "no more agricultural than he is".

"He's using the pellet boiler to heat his mansion house at the taxpayer's expense.

"[It] is in keeping with the mindset of our political elite," the complainant added and they asked Ofgem to investigate and "report to the taxpayers".

After his time in the witness chair yesterday afternoon, Stephen Brimstone is back this morning for potentially a full day of questioning, including plenty more about his biomass boiler.

Mr Brimstone was a DUP adviser for eight years from 2008 and served former first ministers Peter Robinson and Arlene Foster.

He quit his £91,809-a-year job in November 2016, shortly before the RHI debacle erupted.

Image source, RHI Inquiry

The inquiry heard yesterday how he heats his home using a boiler registered to claim generous subsidies on the RHI scheme, which was intended to encourage renewable heat use in non-domestic properties.

But his heating installation falls within the rules of the energy initiative because he also uses it to heat an agricultural shed behind his home.

Mr Brimstone has submitted two statements to the inquiry - you can read them here, external and here, external.

Jayne McCormack
BBC News NI politics reporter

A senior DUP backroom figure accused a former Stormont minister from the party of telling lies about family connections to the RHI scheme.

Jonathan Bell used parliamentary privilege in 2017 to claim that John Robinson (below) was one of two DUP advisers who interfered in the running of the scheme because their families had "extensive interests in the poultry sector".

Image source, RHI Inquiry

Mr Robinson - the DUP's communications director - told the inquiry that Mr Bell had "told lies".

He said Mr Bell's accusation had been "hurtful" and had "catapulted" his family into a "media spotlight, which they did not deserve".

BBC News NI

It is the scandal that sent Northern Ireland's devolved government up in flames and risked leaving taxpayers hundreds of millions of pounds out of pocket.

The RHI debacle has exposed serious flaws in the region's civil service and governance systems.

BBC News NI has followed every minute of the inquiry into the scandal since it started last autumn.

Read our review of some of the major revelations that have emerged so far.

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 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.

Blue skies and sunshine greet us at Stormont on day 95 of the Renewable Heat Incentive Inquiry.

If you were following our coverage of yesterday's proceedings you'll be familiar with the tale of Stephen Brimstone and the biomass boiler in his agricultural shed.

We'll be hearing more from the ex-adviser to the Democratic Unionist Party (DUP) leader and former first minister Arlene Foster this morning - the session starts in the next 15 minutes or so.

Stay with us throughout the day - we'll have a live stream of all of the evidence and text reporting on the key questions and answers.