Frank Dunlop had ready access to Government ministers and was able to arrange meetings with them for his clients.
Yesterday Mr Dunlop said his contacts were across the political divide, but he had no recollection of ever meeting former Environment Minister Padraig Flynn in relation to either the Blanchardstown Shopping Centre or the proposed development at Quarryvale.
Mr Dunlop said he worked for John Corcoran of Green Properties, the developers of Blanchardstown.
Mr Corcoran was anxious to get tax designation for Blanchardstown and had asked the late Brian Lenihan about it.
"I recall Mr Lenihan, prior to a Cabinet meeting, raising the tax designation issue with the Taoiseach, Charles Haughey, but Mr Haughey's response was extremely negative," he said.
"I was told by Liam Lawlor who was told by Ray Burke that Mr Haughey's reply was 'Brian, not today, not tomorrow not (expletive) ever.'"
Mr Dunlop added that Mr Corcoran was concerned that a rival development at Quarryvale would impact on his plans for Blanchardstown. Mr Corcoran wanted to get the tax designation before proceeding to develop the shopping centre.
The former lobbyist told the Mahon Tribunal that it was the late Liam Lawlor who told him to contact Tom Gilmartin and offer his lobbying services for the Quarryvale project.
He wrote to Mr Gilmartin and enclosed press cuttings which dealt with allegations of corruption in the planning process in Dublin.
He knew it was Mr Gilmartin who had made these allegations and agreed with tribunal counsel, Patricia Dillon SC, that a person who made such allegations was unlikely to be involved in corrupt practices himself.
Mr Dunlop said Mr Corcoran was not "best pleased" when he found out that Mr Dunlop had gone to work for Owen O'Callaghan who was then involved in Quarryvale.
His business relationship with Mr Corcorcan had ended rather abruptly around August 1990. He began working for Mr O'Callaghan in 1991.
Mr Dunlop said he made his first corrupt payment in 1991.