It's not been the most revelatory day inside the Senate chamber, but events outside it have raised eyebrows.

After being accused in the House of Commons by the DUP's Ian Paisley of "putting words in the mouth of a witness", will inquiry chair Sir Patrick Coghlin have something to say when proceedings begin tomorrow?

Image source, Press Eye

One thing we can be sure of is that we'll be hearing from Northern Ireland Civil Service boss David Sterling in the morning as he answers the final few questions for this part of the inquiry.

So, join us then and we'll keep you across the details.

Good evening for now!

Returning to the handover note issue that was discussed earlier, Mr Wightman insists he "wasn't trying to hide anything from the inquiry" when he only supplied three of the 14 pages of it in his evidence submisson.

He reiterates that while he found the full document in September 2016 - not long after scheme debacle first became public - he only provided the inquiry with part of it because that's all he could remember receiving when he joined DETI two years earlier.

Image source, RHI Inquiry

Inquiry panellist Dr Keith MacLean says he's "surprised at the conscious decision" not to present the full document.

"It seems odd under the disclosure [request]," he adds.

Mr Wightman says he "knew the inquiry had access to the handover note" through other sources.

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Advance notice of changes to the RHI scheme was circulated to the poultry industry by a civil servant running the initiative, the inquiry has been told.

Mr Wightman claimed his actions had not contributed to a huge spike in applications that threw the budget into chaos, but admits that with the benefit of hindsight he wouldn't have done it.

Image source, PA

In July 2015, he began informal consultation with poultry producer Moy Park and a number of renewable energy companies about proposed changes in the scheme.

The changes would move applicants off a lucrative flat-rate subsidy for 20 years, to a much less attractive one that was capped.

In his written statement to the inquiry, Mr Wightman says he accepts that his "engagement with the industry led to increased awareness of the proposed changes".

After DUP MP Ian Paisley's demand for a personal apology from Sir Patrick Coghlin, the RHI Inquiry has responded.

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A spokesman says the inquiry "does not intend to engage in debate about evidence given to it, outside of its formal hearing process".

He added: "If Mr Paisley, or anyone else, has evidence that they wish to give to the inquiry they should provide it to the inquiry in writing."

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DUP MP Ian Paisley has accused the chair of the RHI Inquiry of "putting words in the mouth of a witness" last week.

Sir Patrick suggested during senior civil servant Teri Clifton's evidence on Thursday that a "lobbying" phonecall she received - which she said involved Mr Paisley - could have been "intimidating".

Mr Paisley said Sir Patrick "went out of his way to sensationalise matters about me", and he told the House that the retired judge "should apologise to me personally".

Back at the Senate chamber, the inquiry hears that Mr Wightman put together a branch plan - a "living" document that was amended as needs required.

Mr Aiken uses 'tracked changes' to comb through the 29 versions of the document from July to December 2014.

The original version includes the passage: "Review biomass tariffs under 100kW" and "consideration of tiered tariffs to prevent excessive payments - check understanding with Peter Hutchinson."

Image source, RHI Inquiry

In his evidence, Mr Hutchinson said concerns over the non-domestic RHI scheme were not raised in his meeting with DETI officials - who didn't include Mr Wightman - and it centred on the new domestic scheme.

Mr Wightman says the consideration of tiered tariffs "moved from being a phase one item, maybe due to our lack of our understanding, to being a phase two item".

The DUP's Ian Paisley has demanded an apology from the chair of the RHI Inquiry over claims that were made against him last week.

A witness told the inquiry that the North Antrim MP had been one of a number of people involved in a phonecall she received, in which she was "lobbied" to accept an application to the RHI scheme after a key deadline had passed.

You can watch the claim by Ofgem official Teri Clifton in the video above.

Speaking in the House of Commons this afternoon, Mr Paisley said no such call took place.

The inquiry breaks for lunch and will be back with more at 14:05.

The original approval for the RHI scheme, granted by the Department of Finance and Personnel (DFP), stipulated that DETI would have to seek reapproval for the initiative in March 2015 in order for it to continue.

This didn't happen.

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Mr Wightman says that he did not check the DFP approval confirmation document when he started in working at DETI.

He had read that the scheme was open until 2020, but he now accepts he should have checked the terms and conditions of DFP's approval.

"I would not have expected the scheme to be subject to reapproval effectively two-and-a-half years after it had come in," he says.

Mr Wightman says he found the 14-page full handover in September 2016 but he only included part of it in his evidence submission to the inquiry.

Asked why he didn't initially provide the inquiry with the whole thing, he says it's because he could only remember receiving the first three pages when he took up his post at DETI in 2014.

Image source, RHI Inquiry

He finally produced the complete document for the inquiry last month.

The inquiry chair, Sir Patrick Coghlin (above), questions why there was no mention of the full document in Mr Wightman's original statement - provided in June 2017 - even though he had been aware of its existence almost a year earlier.

"I accept that point - I should've made it clear," says Mr Wightman.

DETI civil servant Peter Hutchinson was the official who had done most of the development work on the RHI scheme.

He left the department in spring 2014, and gave a 14-page handover note to Davina McCay, who stood into the vacancy temporarily for six weeks until Mr Wightman began took it over.

The note included a list of "urgent actions", including a review of the subsidies on offer through the scheme.

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After they met meet on 26 June 2015, Ms McCay emailed Mr Wightman a full copy of Mr Hutchinson's handover note, which he then forwarded to his personal email address.

In his written witness statement to the inquiry, Mr Wightman says he only received three pages of the handover - containing a staff list and the two-page actions list - and he included them as part of his evidence submission.

But the inquiry has found that he received the full document, and Mr Wightman now accepts that he did receive all 14 pages and he didn't read them all.

There was significant turnover of staff working on the RHI scheme within about six months in 2014 and 2015.

DETI official Seamus Hughes, who worked closely with Mr Wightman on the project, told the inquiry that the level of change was unprecedented in his 36 years in the civil service.

Image source, Getty Images

Mr Wightman agrees, saying he would have expected there "to be at least one cog in the wheel [remain in place], maybe two, for continuity purposes".

But he says a "retention of information" didn't happen because the team working on the scheme was totally changed, and that explains why "key milestones [were] missed".

Mr Wightman admits that had a "very limited understanding" of the renewable energy matters when he joined the team working on the RHI scheme in June 2014.

Mr Wightman accepts that he didn't grasp the extent of the work that would be required in the RHI scheme when he took up his role at DETI.

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There were 77 people working on the Great Britain RHI scheme at the Department for Energy and Climate Change (DECC), and the witness says it was "quite alarming" and he "couldn't believe when I was seeing" when he discovered that.

He saw that there were 13 people at Whitehall doing "what half of me was doing" on DETI's Northern Ireland RHI scheme.

Mr Wightman applied for a transfer to the post at DETI in 2015 because he wanted to gain experience in financial management.

Mr Aiken notes that "there's a horrible irony in this now", given how the RHI scheme's budget spiralled out of control.

Image source, RHI Inquiry

As part of the transfer process he had an informal interview with John Mills, the head of DETIs energy division, who he had worked under at DRD.

In his written statement, Mr Wightman says Mr Mills assured him that "because the RHI scheme was already established and administered by Ofgem on our behalf it would take up very little of my time".

The witness says he was attracted to the post because it offered the opportunity to develop the domestic RHI scheme from the beginning.

During the first 18 months of the RHI scheme, about 130 applications were processed.

An internal document written by Mr Wightman in March 2015 shows that he noted a sizable increase, with a further 470 applications having been received up to that point in the 2014-15 financial year.

That was an "unprecedented increase", he said, mean it was "outperforming" the similar RHI scheme in Great Britain, but it had "impacted on our funding requirement".

It was originally envisaged that just under £12m would be needed to cover the scheme that year, but Mr Wightman noted that the figure had passed the £20m mark.

He wrote that he needed immediate clarity from Stormont finance officials about what the maximum budget would be, because there was a danger that the schemes "may need to be closed to avoid overspends".

Discussing it now, he says "part of this was good news in that uptake was increasing", but he acknowledges that he didn't understand that applications were on the rise because of the scheme's overgenerosity.

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In his written statement to the inquiry, Mr Wightman says he does not feel he was given the "necessary training, resources, project management tools or requisite information to effectively manage" the RHI scheme.

Elaborating on that now, he says aspects of the initiative "would've been quite new to me", and there was no-one to bring him up to speed with the details.

Mr Wightman's two years working at DETI went by like a "blur" because he was so busy "constantly firefighting".

"The telephones never stopped... you're trying to do policy work at the same time you're taking phone calls from people," he explains.

Trying to operate and manage the RHI scheme was "very challenging" given the lack of resources the team responsible for it had.

Mr Wightman makes an affirmation to begin his witness session, with the inquiry's junior counsel Joseph Aiken asking the questions today.

Mr Wightman was head of DETI's energy efficiency branch from June 2014 - in that role, he was responsible for developing renewable heat and energy efficiency policies.

Image source, RHI Inquiry

He had oversight of the non-domestic RHI scheme, and also worked on developing and introducing the domestic RHI scheme.

When he was at the department, he served under John Mills, the boss of the energy division, who he'd also worked with when they were at Stormont's Department for Regional Development (DRD).

You can have a browse through Mr Wightman's written statement on the inquiry's website, external.

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Northern Ireland's top civil servant admitted personal responsibility for failings in the RHI scheme.

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David Sterling told the inquiry that he now felt he should have asked the then enterprise minister Arlene Foster not to go ahead with the initiative, which could end up costing the public purse hundreds of millions of pounds.

But he said he was not sure that even if he and senior colleagues had made that case it would have been accepted by Mrs Foster.

BBC News Northern Ireland

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.