Apple's €13bn tax bill proves to be the 'final straw' for Donnelly
The seemingly sudden departure of Stephen Donnelly from the Social Democrats - the party he helped to found - had been anticipated for some time, according to party sources.
Relations between Mr Donnelly and his co-leaders, Roisin Shortall and Catherine Murphy, have been strained for some time over several issues.
The Herald has learned that the "final straw" was a disagreement over the party's response to the European Commission's ruling that Apple was given a "sweetheart deal" worth €13bn by Revenue.
Ms Shortall and Ms Murphy became "frustrated" after apparently being unable to make contact with Mr Donnelly over a proposed press release outlining the party's stance on the issue.
Hours later, while Mr Donnelly went on radio to offer a measured analysis, his party colleagues were resolute in their view that Ireland should collect the massive sum in back taxes.
However, trouble had been brewing in the party's upper ranks due to the refusal by the party to enter government formation talks.
It is understood that Wicklow/East Carlow TD Mr Donnelly was keen to engage with Fine Gael and Fianna Fail on the prospect of being in coalition.
However, his co-leaders opposed the move.
Several party sources said last night that Mr Donnelly's decision to resign had been anticipated.
The same sources said he told Ms Shortall and Ms Murphy that he intended to use August to examine his position and consider his future.
In a statement yesterday, the party took a swipe at Mr Donnelly, saying he chose to "walk away" from the Social Democrats.
"The levels of dedication required for such a major undertaking can be overwhelming for some," the statement said.
"However, our elected councillors, our staff team and our volunteers are passionate about our project and we will now get on with the job of building our party."
Ms Shortall and Ms Murphy spoke on radio yesterday of their disappointment at Mr Donnelly's decision.
Ms Shortall said he had become "somewhat disengaged" from the party in recent months.
Mr Donnelly did not respond to calls.
However, he told Mary Wilson on RTE's Drivetime programme that being a member of the Social Democrats "just isn't working for me".
He rejected suggestions that he was not a team player and said he felt he could not serve the country to the best of his ability within the Social Democrats' fold.
He also agreed that all politicians should aspire to be in government.
"If you're asking me straight, would I love to be in government one day, then of course I would," he said.
Speculation was growing last night that Mr Donnelly may decide to join another party.
Asked whether he would consider an approach from, say, Fianna Fail, he said the issue was not at the forefront of his mind.
"That's exactly the kind of conversation I'm going to have with my supporters in Wicklow over the next few days and weeks," he added.
Fianna Fail sources told the Herald last night that they were open to the idea of an approach being made to Mr Donnelly.