Timothy Johnston told the inquiry that he had never asked two other Spads to liaise about the RHI scheme or told one of them that there would be no cost controls on the scheme.
A key reason for the delay in cost controls during the summer of 2015 was that Tim Cairns, the Spad to enterprise minister Jonathan Bell, was in contact with Arlene Foster’s Spad, Andrew Crawford.
It is clear that they had a series of discussions about how cost controls should operate and at one point Dr Crawford proposed changes to cost controls which would have had the effect of neutering the department’s attempts to rein in the scheme and preserved generous payments for poultry farmers.
Dr Crawford denies that his intent was to delay cost controls.
Mr Cairns told the inquiry that he began interacting with Dr Crawford about the issue after a meeting with Mr Johnston where he said the senior Spad told him to work with Dr Crawford on the issue and also told him that there would not be tariff controls.
Mr Johnston robustly rejected that.
He said that he had a “very clear recollection of those meetings” where Mr Cairns says the matter arose and he was “absolutely certain that there was no discussion with me about RHI or in fact the other issue [tariff control] in that period at all”
Mr Johnston repeatedly said that he had no interest in the scheme or particular knowledge of it.
He said that he did encourage Mr Cairns to work with Dr Crawford due to the knowledge which Mrs Foster’s adviser had of energy matters.
Sir Patrick Coghlin asked him why he thought Mr Cairns’s recollection that he had said tariff controls would not be introduced was so “very specific”.
Mr Johnston said: “I don’t know” but suggested that Mr Cairns “may have conflated the issues”.
He was also asked about an email which shows that a ministerial submission about the need for cost controls was forwarded to him by Dr Crawford on 1 July 16.
Mr Johnston said that he had “no recollection” of receiving the email, later adding: “I didn’t open that email” which he said arrived when he was on holiday.
But he said it was “entirely possible” that he had a conversation with Dr Crawford about the document.