And what a week it's been, with some of the most intriguing testimony we've heard in the almost 100 days of the RHI Inquiry so far, including a rare insight into the internal workings of the DUP.

Timothy Johnston, who gave an assured performance in the inquiry hotseat, has plenty more questions to answer so he'll return some time in October.

The inquiry panel and the entire cast of RHI characters depart for a well-earned rest.

But they'll be back on Tuesday for another week's cash-for-ash action... and so will we so join us that morning at 09:45.

Looks to be a great weekend ahead - have a good one!

BBC News NI

The DUP's chief executive acknowledged that the party's ministerial advisers were not always appointed in line with regulations.

Timothy Johnston - himself a former adviser who worked with three Northern Ireland first ministers over a 10-year period - said there had been a "drift away" from the proper procedure.

Image source, RHI Inquiry

Inquiry chair Sir Patrick Coghlin suggested that the DUP ignored the rules in an attempt to "centralise power in this party".

Mr Johnston agreed that there had been an "element of centralisation".

Timothy Johnston insists that he knew nothing about the work that two fellow DUP advisers were doing on the cost controls for the RHI scheme in July 2015.

Tim Cairns told the inquiry that he and Dr Andrew Crawford were effectively drawing up a DUP policy to delay the introduction of the subsidy cuts and claimed that Mr Johnston was aware of it.

In his evidence, Dr Crawford said that he mentioned to Mr Johnston that Mr Cairns was "looking for guidance" on the changes to the scheme and emailed him a document outlining what was planned.

When that's put to Mr Johnston, he says it "wouldn't have come as a surprise to me" that the two advisers were working together on the scheme but he doesn't remember it.

Questioned about what happened to the email he received from Dr Crawford, he says he can't remember getting it and didn't open it.

He says that because Dr Crawford was the "expert in this area" he would've know that "there was no input that I was going to be able to give him that was over and above his expertise".

A fellow former DUP adviser is "wrong" to claim that Timothy Johnston ordered that cost controls would not be added to the RHI scheme, he says.

Jonathan Bell's then adviser Tim Cairns told the inquiry that Mr Johnston told him to work with another DUP adviser on the scheme in the summer of 2015 when its big financial problems were becoming clear.

But Mr Cairns wouldn't "go to the sword" on his belief.

Image source, Getty Images

Mr Johnston is "absolutely certain" that there was "no discussion with me" about the scheme at the time.

But he "suggested as a practical, sensible thing to do" that Mr Cairns should refer to Dr Andrew Crawford - his predecessor as the ministerial adviser in the enterprise department - on matters he needed help with.

Mr Johnston claims he didn't have any knowledge of the ins and outs of the RHI at that time and says that Dr Crawford was "seen as our expert on these issues".

Asked if he ever made the "scary TJ call" to the BBC's Stephen Nolan that it had been suggested might kill off queries about the RHI scandal, Timothy Johnston smiles and says he didn't.

"I'm not sure that Mr Nolan would consider any of his communications ever with me in the past to be scary, I hope."

Inquiry chair Sir Patrick Coghlin asks: "Is he a pretty strong personality, is he?"

And with a laugh, Mr Johnston replies: "He considers himself to be..."

Timothy Johnston feels "increasingly uncomfortable" with what he sees as a "media narrative" that he's an all-powerful figure within the DUP.

He sees it differently, explaining that it's "if not unique, certainly unusual" for ministerial advisers to hold their roles for as long as he did.

Image source, RHI Inquiry

As a result of his experience, people valued his input: "The longer you're sitting on the shelf the more vintage you become."

He says that the "longer you're about you're seen almost as a source of power" and he doesn't think it's fair to say there are "one or two individuals who are not elected but who run the show".

"In my view it's not reflective of the role that I played."

It appears that Timothy Johnston was wearing a "number of hats" within the DUP, says Donal Lunny, sometimes a ministerial adviser, at other times a chief of staff or even a chief whip.

The party's chief executive accepts there's some truth to that - he points to the "painstaking work" he did with other Stormont parties to reach political agreements.

"I was always seen as a very political special adviser," he says.

Asked if he could be viewed as the sort of person that one wouldn't want to get on the wrong side of, he says he tries to give advice but doesn't try to force it on people.

But he "wouldn't have shied away from a sense of plain speaking" to people within the DUP.

Timothy Johnston has been described by one former DUP adviser as the "second most important person" in the party, wielding even more influence than the deputy leader Nigel Dodds.

The inquiry has seen plenty of evidence - some of it touched on this morning - that his role as a ministerial adviser went far beyond what it was supposed to have involved.

Among the evidence pointing to his seniority within the party is his involvement in appointing other advisers and his guidance to DUP ministers, MLAs and advisers about how they should respond to questions from journalists.

Image source, RHI Inquiry

And there's more - the inquiry is shown an email exchange between him and Jonathan Bell, in which a forthright Mr Johnston ordered the then enterprise minister to "come down and have a meeting and stop sending emails as if you never had a conversation with any of us in your life".

"Hardly very gracious, JB - let's get sensible," he wrote.

In another instance, the Stormont executive's press chief David Gordon suggested that a "scary TJ call to [Stephen] Nolan" might be in order to throw the BBC off the scent of the RHI fiasco in November 2016, a month before it erupted.

The "importance" of Timothy Johnston's role in the DUP has been "overstated", he claims.

One of the questions the inquiry has been looking to find an answer to is whether there was a heirarchy of ministerial advisers within the DUP and the inquiry panel is fairly convinced that there was.

Former DUP adviser Tim Cairns said that Mr Johnston was "at the top of the tree" in the party when he was a ministerial adviser and his influence was felt from "top to bottom".

John Robinson, another ex-adviser, said that Mr Johnston - who is his brother-in-law - "had a seniority above the other special advisers" and agreed that he was the "most influential".

Mr Johnston says the inquiry has been an "interesting exercise in how other people perceive you".

But he acknowledges that having worked for three first ministers over 10 years he had "greater experience" than other DUP advisers.

Image source, RHI Inquiry

The Senate chamber fills up again, with everyone well fed during the break, and Donal Lunny resumes his questioning of DUP chief executive Timothy Johnston.

Want to watch the proceedings? Click play on the video at the top of this page.

BBC One

The RHI Inquiry was one of the hot topics on The View with Mark Carruthers on BBC One Northern Ireland last night.

The News Letter's political editor Sam McBride, the former SDLP adviser Brendan Mulgrew and Prof Jon Tonge, the author of The Democratic Unionist Party: From Protest To Power, all gave their views on what this week's revelations will mean for Arlene Foster.

You can watch it on the BBC iPlayer here.

Jayne McCormack
BBC News NI politics reporter

The DUP's chief executive acknowledged that the party's ministerial advisers were not always appointed in line with regulations.

Timothy Johnston - himself a former adviser who worked with three Northern Ireland first ministers over a 10-year period - said there had been a "drift away" from the proper procedure.

Image source, Pacemaker

Inquiry chair Sir Patrick Coghlin suggested that the DUP ignored the rules in an attempt to "centralise power in this party".

Mr Johnston agreed that there had been an "element of centralisation".

Lots more to come after the break - Timothy Johnston will be back in the witness chair at 14:00.

Inquiry barrister Donal Lunny asks what responsibility for subsequent failures related to the RHI scheme lies with those who helped to patch up the relationship between Jonathan Bell and his adviser.

"You do these things at the time, maybe not fully appreciating what the consequences thereafter will be," says Timothy Johnston.

Image source, RHI Inquiry

He believes the feeling at the time was that the two men could work together again.

But he accepts the "justifiable criticism" that the process by which the DUP reached that conclusion was "not a sufficiently robust" one.

There was a view within the DUP that the row between Jonathan Bell and his adviser was evidence of a "fairly high degree of unprofessionalism on both men's behalf", says Timothy Johnston.

The day after the clear-the-air meeting, Tim Cairns sent Mr Johnston a text to say that "in my view [Mr Bell] has got away with it again - I do not feel yesterday was fair".

The most senior civil servant at DETI said in his evidence to the inquiry that the "degree of distrust" there was between the two men after the dispute made issues with the RHI scheme "significantly harder to resolve".

Mr Johnston accepts it was a mistake for them to continue working together and if he'd known then what he knows now he would've advised differently.

Timothy Johnston says he would never have spoken to former DUP leader Ian Paisley in the way Jonathan Bell's adviser argued with him.

Donal Lunny puts it to him that if he'd had such a row with any of the three first ministers he'd worked for "you wouldn't have expected still to have a job" afterwards.

Image source, PA

"I think they would have taken a very dim view of it," agrees Mr Johnston.

"I would never have spoken to Dr Paisley like that and I think that if you had you would have been told to get out the door pretty quick."

Jonathan Bell didn't give his adviser an apology but softened his position and "put his arm around" him at the end of their clear-the-air meeting, says Timothy Johnston.

The then DUP leader and first minister Peter Robinson was there at the start of the meeting as a "fatherly figure" to encourage the two men to "move forward together", he adds.

Image source, Pacemaker

Mr Johnston says he disputes the claim by Tim Cairns that he'd been given an ultimatum to either return to work or lose his job with the DUP.

He says that to have said that would've been to effectively take Mr Bell's side and "I didn't see that as my role at that time".

Working for Mr Bell "would not have been straightforward", he says, and the DUP didn't throw people "on the scrapheap" if they were doing a "broadly reasonable job".

Tim Cairns (below) was signed off work by a doctor after the row with Jonathan Bell and the subsequent fallout caused him "stress heaped upon stress".

He told the inquiry that Timothy Johnston said he had two options - reconcile with the minister or lose his highly-paid job.

Image source, RHI Inquiry

A meeting was set up between the minister and his adviser and Mr Cairns claimed that Mr Johnston assured him that Mr Bell would offer an apology.

Asked for his view, Mr Johnston says doesn't remember giving Mr Cairns that guarantee.

"It wasn't clear in my mind that Mr Bell was going to apologise."

The fallout from the breakfast row between Jonathan Bell and his adviser Tim Cairns was "thrown into my lap" to sort out, says Timothy Johnston.

He was involved in meetings to try to resolve it, describing it as a "reconciliation" process to see whether the men could work together again.

Jonathan Bell admitted during one meeting that "he had lost some control" during the dispute, says Mr Johnston.

Image source, RHI Inquiry

Donal Lunny (above) questions whether Mr Johnston's involvement was really part of his role as an adviser, telling him: "It looks a lot more like party management, discipline, personnel."

Mr Johnston says he doesn't accept that it was a disciplinary issue.

But he admits that it was not good that notes weren't made about the meetings and he admits: "It was a dreadful process in terms of how it was conducted."

Timothy Johnston was "quite staggered" when he heard that Jonathan Bell and his adviser Tim Cairns had a row over breakfast during a ministerial trip to London in June 2015.

The inquiry has heard everyone's side of the story - it's all been quite cringeworthy but highly entertaining.

The pair fell out after Mr Cairns tried to advise the then enterprise minister that a decision his department was attempting to proceed with had no support from MLAs would be difficult to pass.

In his account, Mr Bell told the inquiry that he believed Mr Cairns had been challenging "my ability to function as a minister".

Image source, Getty Images

Tim Cairns's evidence is that he was wagging his finger at Mr Bell and told him: "Well, Jonathan, if you want to be the man with big balls and just make the decision go right ahead."

He claimed that after that "inappropriate" comment Mr Bell reached for his finger and threatened to break it, which Mr Bell denies.

Timothy Johnston remembers being told about it all in a phone call from Mr Cairns and his "first thought was: 'This sounds totally out of control'".

"I hadn't ever recalled a situation like that between an adviser and a minister before."