The chief executive of the DUP Timothy Johnston has said he acted in "good faith" on RHI matters following the publication of the long-awaited report into the botched green energy scheme.
The inquiry found that the then DUP special adviser - who denied trying to delay the introduction of cost controls - was "much more involved in the RHI scheme discussions, including tariff controls, than Mr Johnston's evidence to the Inquiry would suggest".
DUP special adviser Timothy Cairns, who worked with DETI Minister Jonathan Bell when the scandal broke, told the inquiry that Mr Johnston had said to delay cost controls.
"The Inquiry considers that the contemporaneous email evidence was consistent with and supports evidence of Mr Cairns that Mr Johnston had made a statement about not introducing tariff controls," the report states.
Mr Johnston, who is now the DUP's chief executive, was an "enhanced participant" in the inquiry process meaning he was given advance sight of the report and allowed to refer to his legal representatives.
He gave evidence to the panel on September 28 and October 4 2018. He also submitted all relevant written material as requested by the Inquiry throughout its duration.
He said he acted in good faith on RHI matters although his involvement "was in many instances limited" and his knowledge of specifics "not comprehensive".
He welcomed the inquiry panel finding no evidence he had acted improperly.
"I apologise for my mistakes at the time and recognise that lessons must be learned," he said in a statement.
He continued: "Following the publication of the final report, I am pleased to note that many of the accusations made on the floor of the Northern Ireland Assembly, under privilege, by a former Minister for Enterprise, Trade and Investment have not been proven, and indeed the inquiry finds no objective evidence to support the allegation made that advisers intervened to keep RHI matters “off the agenda” at meetings."
Mr Johnston said that at the time of the inquiry untrue allegation were made about his actions being taken on "foot of either a financial motivation or other improper motivation".
It was also claimed that named members of his wider family were somehow "involved in installing boilers", which was not the case.
"I welcome the fact that no such findings have been made by the Inquiry and no suggestion is made of any improper motivation on my behalf throughout the period," Mr Johnston said.
"Indeed the Inquiry report is clear that corrupt or malicious activity on the part of officials, Ministers or Special Advisers was not the cause of what went wrong with the Northern Ireland RHI scheme."
Mr Johnston said, as indicated to the inquiry, he "regretted" that he had not read the July 8, 2015 RHI submission describing it as a “missed opportunity”.
"That remains a matter of regret," he said.
"While I am disappointed that the Inquiry Panel, on balance, did not find in my favour on some aspects of my evidence I was grateful for the opportunity to set out my clear recollection of the events at that time.
"The arrangements set up by me between Dr Crawford and Mr Cairns were not intended or foreseen by me as a process to delay the implementation of cost controls.
"I welcome the fact the Inquiry finds that the then DETI Minister was aware of this arrangement and that there were a number of factors that played into the delay in signing off the July 8 submission with responsibility resting with the then DETI Minister and Adviser."
Mr Johnston said the inquiry findings relating to the appointment of special advisers "will come as no surprise".
"To rebuild public confidence it is important that all those involved in political life are not only adhering to the rules but are also seen to do so.
"During my involvement in all matters pertaining to the non-domestic RHI scheme I acted in good faith. While my involvement was in many instances limited and my knowledge of the specifics of the scheme was not comprehensive, I apologise for my mistakes at the time and recognise that lessons must be learned."
He too thanked Sir Patrick Coghlin and his inquiry team for the "fair and professional manner" in which they have conducted the process.
"I also want to put on my record my sincere thanks and appreciation to my legal team, Mr John McBurney and Julie Ellison BL for their patience, time and professional endeavours on my behalf.
"Finally, I am most grateful for the support of my family, friends and colleagues throughout this period."