The head of the regional civil service has conceded that he was never asked not to take notes at meetings between Stormont ministers and officials.
In correspondence seen by The Irish News between Sinn Féin deputy leader Michelle O'Neill and David Sterling, the former permanent secretary at the Department of Enterprise, Trade and Investment says there was never "any general or specific instruction to me not to record meetings between officials and ministers".
Mr Sterling, who was the most senior civil servant in Arlene Foster's department during the development and initial implementation of the Renewable Heat Incentive (RHI), prompted outcry last month after saying a custom developed of not minuting meetings in order to avoid Freedom of Information (FOI) disclosures.
He made the claim while giving evidence to the inquiry into the botched green energy scheme.
The senior civil servant said the practice of taking minutes had "lapsed" after devolution was restored in 2007 when engagement between civil servants and Stormont ministers became more regular.
He told the inquiry that ministers liked to have a "safe space where they could think the unthinkable and not necessarily have it all recorded".
Mr Sterling said the DUP and Sinn Féin were sensitive to criticism and that as a result senior civil servants had "got into the habit" of not recording all meetings.
He said this was done on the basis that it was sometimes "safer" not to have a record that might later be released under FOI.
The civil service head told the inquiry the practice was "fairly common across all departments".
However, following his evidence, former Stormont minister Ms O'Neill wrote to Mr Sterling voicing concerns about his claims.
The Mid Ulster MLA, who previously held both the agriculture and health portfolios, notes that Mr Sterling only served under Sinn Féin ministers for "two brief periods".
She insists that "at no time ever" was the practice of not recording meetings or attempting to frustrate FOI requests ever discussed with Mr Sterling in his dealings with her Sinn Féin colleagues.
"Your assertion in referencing the Sinn Féin party in such public statements therefore ignores inconvenient facts and lacks objectivity," Ms O'Neill wrote.
The Sinn Féin deputy leader said her party "takes very seriously our obligations, duties and lawful responsibilities under the Ministerial Code, and believe that our record in this regard speaks for itself".
"I believe that you have made an error in this part of your evidence by associating Sinn Féin with the type of practices which you described," the letter said.
In his response, Mr Sterling qualifies his comments and insists he did not say that ministers asked or directed that notes of meetings should not be taken.
"Indeed, I am happy to state for the record that no minister who I served in any of the departments in which I worked during the period from May 2007 until the present day ever issued any general or specific instruction to me not to record meetings between officials and ministers," his reply states.
