EAMON Gilmore was reading the Sunday papers at his home in Shankill, south Dublin – and in particular this newspaper's latest set of revelations about John O'Donoghue's expenses – when he made the decision that the Ceann Comhairle's position was untenable.

At five o'clock, a statement was sent out in the Labour leader's name seeking a meeting of the party leaders to consider how the "problem" of the controversy surrounding O'Donoghue's expenses could be "appropriately addressed".

It wasn't immediately obvious to those reading the statement, but an unstoppable chain of events had been set in motion that would result in the Ceann Comhairle's late-night resignation announcement some 53 hours later.

If anything, Fine Gael seemed to be taking the more hardline stance at the time. Through his spokesman, party leader Enda Kenny said on Sunday that he was instructing the three Fine Gael members of the Houses of the Oireachtas Commission to request the Ceann Comhairle to reduce his staffing levels, remove his special adviser Dan Collins from his position and repay any costs incurred not directly related to his office. If these were not addressed, Kenny said, O'Donoghue should consider his position.

But while Fine Gael was going down arguably the more procedurally correct path of dealing with the matter through the Oireachtas commission – effectively the board of directors of the Dáil – Gilmore was determined that this matter would be dealt with in a more public forum.

"He wasn't seeking the meeting of party leaders to enjoy the tea and biscuits," said one close observer, adding that the statement – which pointedly was also sent to the Oireachtas communications unit – was a clear indication that Gilmore believed O'Donoghue would have to go and that it was now about finding a dignified way for that to happen. Even at this point, sources say, he understood that the onus might fall on him to deliver the telling blow to the Ceann Comhairle.

News of the opposition leaders' interventions reached a "very distressed" John O'Donoghue at his home at Cahirciveen on Sunday night. Such public questioning of the Ceann Comhairle would be virtually unprecedented. Reports circulating around Leinster House late last week suggest that, at this point, O'Donoghue seriously considered standing down as Ceann Comhairle and also resigning his Dáil seat. However, having consulted with friends and advisers, he decided not to. Informed sources say these reports were "not inaccurate".

The following morning, on RTE Radio One's Morning Ireland, Eamon Gilmore put clear blue water between himself and Enda Kenny, making it clear that, because it met in private, the Oireachtas commission was not an acceptable forum for dealing with the matter. Gilmore's letter to the party leaders seeking a meeting had invited a response by 2.30pm on Tuesday, when the Dáil was scheduled to reconvene. It quickly became clear that the other party leaders weren't interested in attending the meeting, and it would also become clear that, under those circumstances, Gilmore was willing to act unilaterally.

Later that day, the embattled Ceann Comhairle travelled from Cahirciveen to meet his advisers. The pressure on him continued to build, with Green leader John Gormley joining the chorus for a detailed response to address the controversy which he described as a "running sore".

At 5.20pm, a short statement was released by O'Donoghue promising he would present "detailed proposals" to the Oireachtas commission to allay concerns about his expenses and the views of the three party leaders – Kenny, Gilmore and Gormley – would inform those proposals. It may not be true that on Sunday night he was considering leaving politics altogether, but it is clear that, by the following afternoon, O'Donoghue was preparing to stand his ground.

But that position was undermined further by reports in the following morning's Irish Times, which had details from Horse Racing Ireland of expenses of more than €20,000 incurred by O'Donoghue when he attended racing festivals in Melbourne, Aintree and Cheltenham during his time as sports minister.

That morning, Eamon Gilmore was in O'Donoghue's home county attending the Siptu conference in Tralee. Departing from his script, Gilmore emphasised that nobody should underestimate his determination to deal with the O'Donoghue issue.

On his way back to Dublin, Gilmore received a call from O'Donoghue on his mobile. According to an internal memo prepared for government, details of which were published in the Irish Times on Thursday, O'Donoghue informed Gilmore that he had just received notice from Sinn Féin of a motion calling on the Ceann Comhairle to resign. He told Gilmore that reports in the media were inaccurate and misleading and asked that, rather than doing anything "precipitous", he would allow the Ceann Comhairle the opportunity of putting his case before the Oireachtas Commission the following evening.

Gilmore said he would consider what O'Donoghue said and would come back to him. He phoned the Ceann Comhairle shortly afterwards, telling him that he did not think he could survive in his position and that it was "not looking good". O'Donoghue again insisted that the media coverage of his expenses was "in many respects incorrect and misleading" and pleaded to be allowed to put his case to the commission, arguing that he was only asking for natural justice and seeking the same rights and respect as would be afforded to any citizen under the constitution.

Although it does not appear to be contained in the memo, it is understood that Gilmore suggested that the Ceann Comhairle take the matter out of the hands of the Oireachtas commission and make a public statement, preferably in the Dáil. This was not acceptable to O'Donoghue.

The conversation ended with Gilmore saying he would "chew on it" and would ring him back. There were no more phonecalls.

It is clear that, despite the impression circulating on Tuesday night, Gilmore did not bluntly tell O'Donoghue that he was going to table a confidence motion – an omission of which Fianna Fáil deputies are hugely critical. But sources close to the Labour party say Gilmore made it clear the game was up.

The next communication between the two men came a few hours later across the floor of the Dáil. A nervous-looking Gilmore amazed the house by stating that O'Donoghue's position was no longer tenable and that he would have to resign or be removed from office. The game was indeed now up. A stunned O'Dono­ghue, his voice almost breaking, barely got the words out to thank "Deputy Gilmore".

It was now a matter of when, not if, O'Donoghue would go. Given the non-party political status of the position, continuing as Ceann Comhairle without the support of the opposition was impossible, a point underlined when Enda Kenny came out just after 6pm to declare that in the interests of the independence of the office, O'Donoghue should resign forthwith. Kenny's new line seemed to contradict his earlier stance that the matter should be dealt with through the Oireachtas commission. Fine Gael was clearly playing catch-up.

It still took more than four hours for the inevitable to happen. A shattered O'Donoghue took refuge in his office. He received some visitors there and the taoiseach was also keeping in contact with him. Cowen, on his way back up from the parliamentary party meeting, dropped into John Gormley and asked him what his thoughts were about the Ceann Comhairle's position. He didn't try to persuade the Greens to back O'Donoghue – several Fianna Fáil deputies wouldn't have countenanced such a move – but Gormley made it clear that the party could not support the Ceann Comhairle in a contested vote.

O'Donoghue was informed of this but asked Cowen that Gormley and the Greens be sounded out a second time; they were, but the answer was the same. The Green leader also reiterated his position in a third conversation, this time by telephone, with Cowen.

At 8.30pm, O'Donoghue decided to go but made it clear he wanted space to put his affairs in order. This prompted a flurry of telephone calls between the offices of the various party whips to agree a schedule for his departure. Labour, perhaps mindful that it had been the one to pull the trigger, was inclined to give O'Donoghue that space, but Fine Gael preferred immediate resignation. After much toing and froing, a resignation statement went out at close to 10.30pm.

It was all over bar the recriminations, and there are plenty of those. There is enormous bitterness in Fianna Fáil at what was seen as the opposition trying to "trump each other" in a "race to the bottom for the vote". Accusations abound that Gilmore was concerned only with "a quest for self-publicity" at the expense of due process. Labour sources admit there was a "chill wind" blowing in the party's direction, not just from Fianna Fail but from its would-be coalition partners, Fine Gael.

Within Fine Gael, there is irritation that it was Gilmore rather than Enda Kenny who got the public kudos for showing leadership and bringing an end to the whole sorry affair. Almost certainly, this was the reason for the party's rather hollow-sounding insistence the following morning that O'Donoghue should go immediately, instead of the following Tuesday, and that he was somehow trying to have an each-way bet in case the Greens opted to withdraw from government this weekend.

It was with a certain relief that deputies, emotional about the week's events and reeling from the public's reaction to what is seen as an expenses gravy train, headed home for the weekend.

The only person keeping his counsel is the (soon to be former) Ceann Comhairle, John O'Donoghue. But that will change this Tuesday.