Former Stormont first minister Peter Robinson has said he did not ask a DUP special adviser to forward sensitive government documents to his lobbyist son.
Andrew Crawford told the RHI inquiry on Thursday that he emailed a privileged legal letter to Gareth Robinson.
The document related to the Department of Enterprise, Trade and Investment's high court challenge against the then environment minister Mark H Durkan's adoption of the Belfast Metropolitan Plan – effectively scuppering retailer John Lewis's plans for a store at Sprucefield near Lisburn.
It was one of several internal documents that Mr Crawford shared with associates outside the department while working as a spad for then enterprise minister Arlene Foster.
He told the inquiry he may have been asked for the information by either Peter Robinson or the former DUP leader's then adviser Richard Bullick.
Mr Crawford said that because it involved his party leader's son he usually "responded to his queries quicker" than to queries from other lobbyists.
But Peter Robinson told the BBC that he did not ask the former DUP spad to send this information to his son – or did he ask his special adviser to ask Mr Crawford to send it.
He said he was not aware of Mr Bullick asking Mr Crawford to send the information.
Mr Bullick was unavailable for comment.
Ulster Unionist MLA Steve Aiken last night called for the head of the civil service to investigate the unauthorised release of confidential documents.
"To actually find that documents that have been described variously as protected or confidential, or whatever else, was being leaked, and being leaked by a special adviser, that brings into whole question of what is going on with classified documents," he said.
