Key Mahon Tribunal witness and businessman Tom Gilmartin has died.

In a statement, his family said he died peacefully at Cork University Hospital this morning.

"We will greatly miss a much loved husband, father and grandfather," the statement said.

"We mourn the loss of a truly honest, honourable and courageous man."

In an infamous Late Late Show interview, former Fianna Fáil TD Pádraig Flynn spoke about knowing Mr Gilmartin.

He said that neither Mr Gilmartin, nor his wife was in good health, describing Mr Gilmartin as "out of sorts".

Up to that point there was still uncertainty about whether Mr Gilmartin would give evidence to the early phase of the Tribunal.

However, on hearing Mr Flynn's remarks, Mr Gilmartin decided to co-operate.

Mr Gilmartin, a successful businessman in the UK, came back to Ireland in the late 1980s and identified two potential retail developments in Dublin, one at Bachelor's Walk and the other at Quarryvale.

Mr Gilmartin would later allege that money was demanded from him at various stages by politicians and councillors.

It was Mr Gilmartin's allegation that former Taoiseach Bertie Ahern had received money from Cork developer Owen O'Callaghan that culminated in the then Taoiseach appearing before the Tribunal.

Mr Gilmartin also told the Tribunal that Mr Flynn requested a cheque for IR£50,000 as a donation to the Fianna Fáil party, on the understanding that steps would be taken by Mr Flynn to ease or remove obstacles and difficulties which the developer was facing in relation to the Quarryvale site.

The Tribunal's report found that the former minister and EU Commissioner "wrongly and corruptly" sought the donation and having been paid IR£50,000 by Mr Gilmartin for that purpose, proceeded to use that money for his personal benefit.