STORMONT'S finance department was "backed into a corner" to approve more funding for RHI, the inquiry into the botched scheme has heard.
Officials in the Department of Enterprise, Trade and Investment (Deti) which ran RHI needed approval from finance officials on a business case which included cost control plans to tackle spending concerns.
But Deti was already pressing ahead and discussing the planned RHI changes with industry before receiving sign-off from the finance department.
The inquiry heard the business case contained false claims that the RHI scheme had been reviewed and that approval under EU state aid rules had been secured.
Emer Morelli, head of supply at the Department of Finance, was returning to the inquiry yesterday having attended back in June.
She said the department's only option was to approve Deti's business case, as it would have delayed autumn 2015's introduction of cost controls.
Inquiry barrister Joseph Aiken suggested that finance officials were being "backed into a corner, whether intentionally or otherwise".
He asked Ms Morelli: "Intentionally or otherwise, by the time it [the business case] comes to you in October, the ship has sailed?"
She responded: "Very firmly sailed."
Finance and Deti officials met at the end of September 2015 to discuss why a business case had not yet been submitted despite changes due within weeks.
Ms Morelli said Deti officials claimed RHI had delivered value for money and needed to continue for job prospects in Northern Ireland.
She accepted finance officials should have asked questions earlier and been "more proactive" in gaining an understanding how the RHI budget worked.
But Ms Morelli said "no alarm bells" were ringing because Deti gave no indication that "this was a scheme that was out of financial control".
The inquiry also heard it took a Deti official six months to receive approval for minutes for a key meeting in October 2015.
Mr Aiken suggested the inquiry panel's recommendations could include a time limit for the completion of minutes.
Ms Morelli also told how in early 2017 Sinn Féin's Máirtín Ó Muilleoir, then finance minister, revoked her delegated authority to approve plans to address the RHI overspend.
She said she was not aware of a minister taking such action before, but "we were in such unique times" and Mr Ó Muilleoir was "totally entitled" to ensure he was content with the plans being developed.
Launched in 2012, the non-domestic Renewable Heat Incentive (RHI) was designed to encourage businesses to switch from burning fossil fuels to more sustainable alternatives.
But the subsidies were worth more than the cost of wood pellets, encouraging firms to 'burn to earn'.
Delays in introducing cost controls brought a spike in applications and pushed the multi-million-pound government scheme hugely over budget.
The inquiry will today hear again from Andrew McCormick, Deti's former permanent secretary.
