Property developer Mr Dunne bought the site of the Jurys and Berkeley Court hotels in Ballsbridge for €379m in 2005.
Ulster Bank loaned €325m of the total amount.
Mr Dunne had originally agreed with Bank of Ireland and Irish Nationwide Building Society to finance the deal. However, Ulster Bank approached Mr Dunne about taking over the funding of the transaction.
Ulster Bank and Bank of Ireland both declined to comment.
However, the Irish Examiner has spoken to a number of former Ulster Bank executives about the ill-fated deal.
Ulster Bank was under huge pressure from its parent company, Royal Bank of Scotland, to grow profits in this country. Executives from the bank contacted Mr Dunne about taking over from Bank of Ireland and Irish Nationwide in the landmark deal.
Terms were agreed over a two-day period, including going through an RBS credit committee in London.
Mr Dunne planned a €1.5bn ‘Knightsbridge’ type development in Dublin 4, comprising a 37-story tower with high-end apartments, a hotel, retail and office units.
Planning permission was turned down by An Bord Pleanála on the original proposal, although a revised model was resubmitted.
However, when the property market crash in 2008 wreaked havoc across the banking system, the crisis caused the near-collapse of RBS. It is now 82% owned by the British government.
Fred Goodwin, the chief executive at the helm of RBS during the boom years, who was responsible for driving the bank’s unsustainable growth, has been stripped of his knighthood.
RBS has had to pump over £15bn (€18bn) into Ulster Bank since 2008.
There have been a number of management changes at the Irish bank over the past few years and New Zealander Jim Brown has been brought in as the new chief executive.
Ulster Bank and a series of other banks have registered a €164m judgment against Mr Dunne in respect of the loans extended for the Ballsbridge deal.
Mr Dunne now lives in the US and could not be contacted at the time of going to press.