The explosion of a relatively minor controversy into a government-threatening scandal has come at a disastrous time for Micheál Martin, who is already facing criticism over his public appointments, his handling of the Covid-19 crisis and his pro-unionist statements on the issue of Irish Unity.

A 2016 conviction for drink driving, for which Mr Cowen had been penalised in the usual manner, had previously been unknown. Publicised last week, likely as part of a whispering campaign against him by party rivals, the transgression brought about a showdown with Micheál Martin which last night ended his Ministerial career.

Minister Cowen issued a stern statement in his defence. “The decision of the Taoiseach to remove me from office, when he supported me this afternoon in the Dail, has undermined and potentially prejudiced my entitlement to fair process,” he said.

Murmurings over the appointment of Mr Cowen, a brother of former Taoiseach Brian Cowen, continued for two weeks amid resentment within Fianna Fáil over the exclusion of more senior party figures from the newly constituted coalition Cabinet.

Martin insisted that Cowen’s refusal to address parliament on the matter had given him “no choice” but to sack him, ending one of the shortest tenures of a Minister in Irish history.

Sinn Féin leader Mary Lou McDonald asked Mr Martin if he had misled the parliament over his knowledge about the incident.

The Taoiseach denied that he knew the full “sorry story” over a week ago. He claimed he was unaware until a few days ago of the details of the file or allegations -- strenuously denied by the Offaly TD -- that he had attempted to evade a Garda checkpoint.

Explaining his decision to sack Mr Cowen after publicly backing him just hours earlier, Mr Martin said the former minister had taken “a legalistic approach to defend his rights”.