“I am proud to belong to Fine Gael, a party with the highest ideals, values of honesty and integrity, whose members have always put the country rather than the individual first," he said at the time. 

"To avoid any possibility of damaging a Government led by Taoiseach John Bruton - a man of the utmost decency and outstanding qualities - I have tendered my resignation from Government and it has been accepted."

Mr Hogan, a Kilkenny native, entered national politics in 1989 winning a seat for Fine Gael in the Carlow/Kilkenny constituency, having served two years in Seanad Eireann.

In his early years in the Dáil, he held a number of frontbench positions in opposition.

Between 1989 and 1994 when Fine Gael entered government, he served as spokesman on food, forestry, consumer affairs and then regional affairs and European development.

Known to be close to John Bruton, he was appointed a minister of state at the Department of Finance in the Rainbow Coalition with the Labour Party and Democratic Left.

Seen as the fall-guy in the budget leak affair, Mr Hogan was later elected as chairman of the Fine Gael parliamentary party.

In 2002, Fine Gael suffered a disastrous election where they won just 30 seats and culminated in the resignation of Michael Noonan as leader.

Mr Hogan contested the leadership contest but lost out to Enda Kenny.

For the second time in a row in 2007, Mr Hogan was appointed as Director of Organisation for the general election that year which saw Fine Gael win 50 seats.

In 2010, during the botched heave against Mr Kenny, Mr Hogan played a pivotal role in seeing off Richard Bruton’s challenge and was rewarded by his leader when Fine Gael and Labour were swept to power in 2011 with a Cabinet ministry.

As Minister for the Environment, Mr Hogan had responsibility for overseeing the introduction of Irish Water, which by any standard was a calamity.

He also oversaw the abolition of 80 town councils, which was introduced at a time of austerity. 

In what was seen as payback for helping him survive, Mr Kenny rewarded Mr Hogan with the plum job of Ireland’s Commissioner in 2014, despite his perceived mishandling of the Irish Water issue.

His successor as Environment Minister, Alan Kelly, slammed Mr Hogan’s handling of the issue, saying: “I was handed the greatest hospital pass in Irish political history.” Mr Hogan is said to have guided Mr Varadkar in his bid to become the leader of Fine Gael in 2017 and was duly rewarded in 2019 with a second term as Ireland’s EU Commissioner.

Seen as an effective operator, Mr Hogan was given the highly powerful trade portfolio by new President Ursula von der Leyen which was seen as a major achievement for Ireland.

His departure in the current circumstances is a blow in the context of the ongoing difficult Brexit negotiations.