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An extended afternoon session comes to a close, ending what's been a captivating couple of days with Mr Stewart in the witness chair.

Tomorrow is the inquiry's last day before it breaks for the summer and it promises to be an intriguing one as senior figures from the poultry giant Moy Park face questions about their firm's role in promoting the scheme to its suppliers.

Join us from 09:45 - until then, goodbye!

BBC News NI

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The inquiry has been told that there was an attempt to "protect" Arlene Foster during the closure of the RHI scheme, it emerged.

It was revealed by senior civil servant Chris Stewart that a former DUP adviser has made a reference in his witness statement to protecting the former first minister from blame.

Mr Stewart also said there was a "desire" in the DUP to make it appear that former enterprise minister Jonathan Bell had sole responsibility for what was an unpopular decision to shut down the scheme in 2016.

The closure of the RHI scheme faced a final day of two weeks, leaving it open for applications until 29 February 2016.

Mr Stewart says the decision to push back the closure was "an understandable political response to lobbying from stakeholders".

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But he admits that the decision was taken without any reference to the extra cost that would be incurred by the delay.

He became aware in February 2015 of communication from the poultry giant Moy Park to its suppliers that advised them to act quickly to get applications in for the scheme before it shut, which left him "surprised and dismayed".

Mr Stewart objects to Mr Bell's characterisation of him during his interview with the BBC's Stephen Nolan in December 2015 as someone who went to the minister as a "whistleblower", describing it as "simply wrong".

He explains that senior civil servants in Northern Ireland can find themselves working for ministers from parties with widely differing views as there is a permanent coalition.

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"You can only do that if you have the trust and confidence of all ministers and all parties," he says.

If he was viewed as a whistleblower it would make it very difficult for him in the future "to enjoy the trust and confidence of any political party, not just the DUP".

Mr Bell gave an "obvious angry reaction" when Mr Stewart later told him that it was he who had removed the reference to Arlene Foster from the submission about the closure of the RHI scheme.

It then became "instantly clear" that the minister had not made the request for the change to be made, says the witness, and his anger was "fully justified".

Shortly afterwards, Mr Cairns joined the meeting and when he was challenged by Mr Bell about the change he suggested that Mr Stewart had lied to the minister, according to Mr Stewart's account.

"Tempers rose quickly," says the witness and Mr Cairns withdrew that claim shortly afterwards.

There was a "desire" in the DUP to make it appear that Jonathan Bell had been solely responsible for the decision to close the RHI scheme without public consultation, says Mr Stewart.

He says there's a reference in Mr Cairns' witness statement to "protecting " Arlene Foster that suggests there was a "strategy emerging" to protect the first minister from the fallout.

He agrees with the inquiry barrister's suggestion that closing the scheme would be a "politically unpopular decision" and therefore there was an attempt for "full responsibility" for it to be attributed to Mr Bell.

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Mr Stewart says he didn't know at the time that the attempt to remove references to other ministers in the DETI submission was "against [Mr Bell's] wishes".

The inquiry chair Sir Patrick Coghlin tells him that Mr Cairns was therefore "representing something that was false" when he had requested that the changes were made to the document.

In a BBC interview in December 2016, Jonathan Bell claimed that DUP advisers tried to "cleanse the record" by removing references to Arlene Foster from a paper about the RHI scheme.

That paper was a submission from the start of February 2015 about the decision to close the scheme without a public consultation.

The original document stated that the decision had been reached after the minister had discussions with the first minister and the finance minister.

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The adviser Tim Cairns asked Mr Stewart to remove the references to other ministers, saying that Mr Bell had "made the decision... and no advice from other ministers or departments played a part in that".

Mr Stewart says that was "factually incorrect and rather strange" because he knew otherwise: "These contacts had taken place - it simply wasn't possible to deny that they had."

The reference to the first minister was removed on the basis that it was Mrs Foster's advisers who had been consulted, not the minister herself, but the one about the finance minister remained in the document.

Mr Bell's adviser Tim Cairns asked civil servants to request that the Northern Ireland Assembly committee process be "bypassed" in order to get the RHI scheme as quickly as possible.

Mr Stewart says it was a "bizarre" request, one that was intended to "bypass their entire legislative process".

Consensus emerged between the DETI minister Jonathan Bell and finance minister Mervyn Storey that the RHI scheme should be closed without a public consultation, according to Mr Stewart.

He felt that a consultation was necessary to avoid the risk of legal challenge to the decision but "the tide had turned against us at that point".

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Matters were "moving so quickly" that civil servants were trying to "catch up and create some sort of record of what had happened".

"It felt very uncomfortable, it felt very unusual," he adds and while he wasn't concerned that it was improper it was certainly "unorthodox".

A draft DETI paper on the RHI scheme that was to go to the Northern Ireland Executive was passed to the finance department for comment.

The paper came back with some suggested amendments - the finance department wanted to remove a section referring to "the poultry industry's use of broiler houses".

Mr Stewart objected to the removal of the text as it was factually accurate but the section was taken out of the final version that went to the executive.

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The DUP adviser Dr Andrew Crawford was working with the finance minister Mervyn Storey at that point.

Mr Stewart's view is that the suggestion for removal came from Dr Crawford and was because he "would have a better understanding of the agriculture industry than I do felt that it was actually factually incorrect".

That, he adds, is pure speculation on his part.

DUP and Sinn Féin ministerial advisers met at short notice at Stormont Castle to discuss what should be done about the closure of the RHI scheme.

Mr Stewart was also there and he remembers"there was quite a considerable measure of agreement" between the parties to get it shut it down without a public consultation.

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He says that "Sinn Féin were even more keen on moving quickly than the DUP".

But he adds that the DUP advisers felt that civil servants were being "too cautious" and needed to "move more quickly" to stem the spend on the scheme.

Dr McCormick wrote to Mr Stewart advising him that the RHI crisis was now a matter for the then first minister Arlene Foster - she'd taken the role on just a couple of weeks earlier - and the head of the Northern Ireland Civil Service, Dr Malcolm McKibbin (below).

Dr McKibbin, who'd been copied into the McCormick email, wrote back saying the first minister "has made it quite clear" that it was DETI's responsibility of DETI to "mitigate costs and to urgently cease accruing further liabilities".

Mr Stewart says he was "very surprised by it and I didn't understand it".

Asked how the confusion came to be about which department was responsible for handling it, he says: "I really can't provide an illuminating answer on that."

The crisis was escalated through Stormont's finance department and the first and deputy first ministers' office as well as to the head of the Northern Ireland Civil Service.

The then DETI permanent secretary Dr Andrew McCormick (below) expressed his frustration with the delay in getting the RHI scheme's closure approved to his then finance department equivalent David Sterling.

"The issue is where it is. There's nothing more Chris or I can do to shift it - unthinkable this is delayed any further," he wrote in an email.

Mr Stewart describes that as "fairly direct language" and says it made the point that even senior civil servants "had limited or any ability to influence" the situation.

It's not unusual for policy decisions to be considered by political party advisers, says Mr Stewart.

"What is unusual is for that to happen after a minister has purportedly cleared the [submission]."

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He didn't know whether the minister had been persuaded to rescind his decision or if it had been done for him.

Based on emails he has seen, he says: "I think the minister was confused as to what the position was as well."

Official approval was given by Jonathan Bell to close the RHI scheme on 22 January 2016 but it was rescinded about 20 minutes later.

Asked who was responsible for that, Mr Stewart says it was "clearly not" rescinded by the minister but he isn't pinning it on anyone.

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He says he has never before or since "remember a submission being uncleared" and it caused "puzzlement" but he feels that DETI's energy boss John Mills was "more suspicious" and viewed it as a "delaying tactic".

Mr Mills told the inquiry last week that he thought there were "very disturbing reasons for it", one of those being that it would "allow people to make applications before closure".

The minister's adviser Tim Cairns said the submission was in the hands of "DUP party officers" - Mr Stewart took that to mean that DUP ministerial special advisers, referred to as spads, had it.

DETI needed to act quickly to get the scheme closed and a submission was sent to the minister Jonathan Bell on 19 January 2016, advising that a public consultation on the matter should be approved for issue the next day.

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The department had to get the consultation out quickly in order to allow the legislation to pass before the Northern Ireland Assembly rose for an election in March that year.

The submission was marked "immediate" - Mr Stewart explains that that was necessary in order to get it put straight on to the minister's desk as "too many things are marked 'urgent'".

Time to grab a snack and catch some rays - the inquiry returns at 14:00 for the afternoon session.

On New Year's Eve 2015, the then enterprise minister Jonathan Bell (below) was told in a ministerial submission that he had "no choice but to close" the RHI scheme as soon as possible.

Mr Stewart says it was "decision time" for the minister and Mr Bell agreed to the closure at a meeting on 11 January 2016.

In "contrast" to the cost controls saga of the previous summer, he says Mr Bell's adviser Tim Cairns offered no resistance but he adds: "It would've been a brave man or woman who would've opposed the rationale that we needed to close."

Asked what the reaction was from Mr Bell and his adviser, Mr Stewart says he doesn't remember any anger or the apportioning of blame at that stage.

"I think we were all a bit shell-shocked at the situation we'd found ourselves in," he says.

"I think there was a recognition on the ministers part and on Timothy's part as well that this was a very, very serious situation - it was a catastrophe."

DETI officials held out hope for much of December 2015 that the Treasury would agree to take at least some of the hit of the massive overspend on the RHI scheme.

But on 21 December the Treasury "put absolutely beyond doubt" that it wouldn't be picking up the bill, says Mr Stewart - yesterday he described that as a "day of complete dismay".

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After that point, the scheme became a "full-blown crisis" as the race was on to get the scheme closed - he says he then took a much more hands-on role in dealing with it.

Mr Scoffield says he has "no doubt" that some people would've had their "Christmases wrecked that year by virtue of what had happened and what needed to be done".

Mr Stewart says he regrets not heeding a warning from a civil servant that there was "no choice" but to shut down the RHI scheme as applications were flooding in.

Stuart Wightman, who was managing the scheme, emailed Mr Stewart midway through November 2015, telling him that there'd been 800 applications in the previous six weeks.

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That was a "brave and significant step", says Mr Stewart.

But he didn't immediately act on it and it wasn't until more than three weeks later that he "reached the view that closure or suspension was required".