BBC News Northern Ireland

Former enterprise minister Arlene Foster and a senior civil servant had sharply diverging memories about a series of meetings when the RHI scheme was being set up, the inquiry heard.

Image source, Press Eye

In her written evidence to the inquiry, Mrs Foster has claimed that advice she received led her to believe that an ongoing subsidy scheme model for the RHI scheme gave the "highest potential heat output at the best value", when in fact another option would've been better in that regard.

But Mrs Hepper told the inquiry that she has a "clear recollection" of the meeting she had with the minister at which the issue was discussed.

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, centre), 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) leader Arlene Foster (below) faced calls to resign from her role as Northern Ireland's first minister in December 2016.

Image source, Getty Images

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, more than a year 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 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.

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.

Welcome to our Friday coverage of the Renewable Heat Incentive Inquiry.

Image source, Press Eye

There may be a packed weekend of sport ahead, as they say on the radio, but this morning all eyes - well, ours at least - are on Stormont's Senate chamber.

Fiona Hepper, the former head of energy division at The Department of Enterprise, Trade and Investment (DETI) is continuing her evidence, with proceedings beginning shortly.