Mr Scoffield now turns to two further detailed witness statements Mr Bell has provided to the inquiry.

Mr Bell alleges communications between him and the department were overseen and filtered by his SPAD Timothy Cairns.

He says the communications between Mr Cairns and the DETI permanent secretary were of concern to him - particularly in relation to RHI.

"The picture painted by Mr Bell is that even though he was the minister he was on occasion kept in the dark about what was going on in his department," says Mr Scoffield.

Mr Bell says that on one occasion, after a disagreement with Mr Cairns, he was told by Timothy Johnston (seen above), the first minister's SPAD, that Mr Bell was not in charge of his own special adviser and that only the DUP party officers could give instructions to the adviser.

Mr Scoffield says the inquiry will want to consider whether the concerns expressed by Mr Bell impeded effective decision-making concerning the RHI scheme.

Mr Scoffield takes the panel through the BBC's Nolan TV programme.

In the interview, Mr Bell claims that two senior DUP advisers "were not allowing this scheme to be closed" at the point when costs were spiralling out of control in autumn 2015.

According to former enterprise minister Mr Bell, the advisers, who deny the allegations against them, secretly tried to "cleanse the record" of references to Mrs Foster.

Mr Scoffield points out that it is not in the inquiry's remit to examine all of Mr Bell's claims, but what is claimed in the interview about cost control and the allegation that he was thwarted from closing the scheme.

"You're saying there was a conspiracy against him?" asks Sir Patrick.

"His comments in the interview say that he was being openly thwarted," says Mr Scoffield.

Mr Scoffield brings to the attention of a panel a crisis meeting organised by permanent secretary of the Department of Enterprise, Trade and Investment (DETI), Andrew McCormick.

This "crisis summit", as Mr Scoffield calls it, was held in June 2015.

The meeting found that a full review of the RHI scheme should have been conducted in 2014 to 2015, that re approval for the scheme should have been sought and, unlike the GB scheme, the Northern Ireland RHI scheme did not have a tiered tariff or digression.

Image source, Getty Images

A subsequent '"issues meeting" with minister Bell on 8 June was the first time he was made aware that there was a serious issue with the scheme.

Meanwhie, the departent had taken legal advice tose whether it could imose a temporary suspension of the scheme for ew applicants.

The answer came back from the departmental Solicitors Office was that his would require legislation, and the department started preparing new regulations to go before the assembly

Image source, Getty Images

Phase three will pick up the RHI scheme story in July 2015.

Mr Scoffield says his aim today is to set the backdrop to the oral evidence that will begin next week.

Yesterday, Mr Aiken summarised the phase two evidence, which brought the inquiry up to May 2015.

A submission in July 2015 is the starting point for the inquiry's next phase.

Mr Scoffield says this submission and a supplementary statement from the Department for the Economy (DFE) will be key to the inquiry.

Mr Scoffield says the next stage of the inquiry will likely keep its focus on the events before the suspension of the RHI scheme to new applicants in February 2016.

Given the proximity of the events, he says, phases three and four of the inquiry will be run concurrently.

He also expects these phases to be less technically complex and look at a shorter time frame.

These phases will start next week and continue on a two weeks on, one week off, basis until the end of June.

We can plenty of interesting faces to give oral evidence, like:

• Former DUP minister Jonathan Bell (seen above)
• DUP leader Arlene Foster Special advisers - or SPADs for short.
• Outside government stakeholders.

Mr Scoffield explains that over the next two hearing days he'll be looking at the period July to November 2015 - the introduction of cost controls and when there was a significant spike in applications to the scheme.

He'll then take us from November 2015 to February 2016 when the scheme was closed to new applicants.

"The inquiry has no Phase 5 and you'll be pleased to hear that I don't intend to propose one," he says.

Image source, RHI Inquiry

He notes that this was by no means the end of concerns about the scheme - referring to the political fallout of the auditor general's report on the scheme in July 2016, and the appearance of former DUP minister Jonathan Bell on the BBC' Nolan TV programme in December.

Mr Scoffield also mentions the department's attempts to address the anticipated overspend, which is subject to a current legal challenge.

Inquiry senior counsel David Scoffield QC is conducting the opening for phase three and four of the inquiry. These phases will consider the the introduction of revised subsidies and a usage cap for new scheme claimants in 2015, and the scheme's closure.

We'll be hearing a lot from Mr Scoffield over the next few days.

Image source, RHI Inquiry

By the end of today we should have a better idea of where the inquiry is headed next. This can seem a rather dry process but stick with it - we've had some fasciating wee gems appear during previous openings.

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 concernand 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) leaderArlene Foster faced calls to resign from her roleas Northern Ireland's first minister in December 2016.

She resisted, and Sinn Féin'sMartin McGuinness then quit as deputy first ministerin 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 inour 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.

Image source, Reuters

Welcome to Stormont's Parliament Buildings for Day 70 of the RHI inquiry.

We've a change of gear today as the inquiry grinds inexorably towards the completion of the hearings - don't hold your breath though, that's still months away.

There are no witnesses in for a grilling - instead we have the openings for phases three and four of the inquiry.

This includes the period when it became apparent that things were not all as they should have been on planet RHI, and some of the political fallout.

All will be revealed - stick around for the live updates starting at 09:45