EU trade commissioner Phil Hogan has resigned after the Irish government accused him of breaching Covid-19 guidelines.
Mr Hogan attended a golf dinner with more than 80 people in County Galway on 19 August.
He was also criticised for not complying with quarantine rules when he arrived in Ireland from Brussels.
Mr Hogan said he did not break any law but he “should have been more rigorous” in adherence to the Covid guidelines.
In a resignation statement, the outgoing commissioner said he regretted his trip to Ireland had “caused such concern, unease and upset”.
“I reiterate my heartfelt apology to the Irish people for the mistakes I made during my visit,” he added.
On Tuesday, Mr Hogan provided details to the President of the European Commission, Ursula von der Leyen, about his time in Ireland leading up to his attendance at the Oireachtas (Irish parliament) Golf Society event.
After arriving in the Republic of Ireland on 31 July, Mr Hogan said he travelled to his temporary residence in Kildare and tested negative for Covid-19 on 5 August during a hospital visit.
He had told Irish state broadcaster RTÉ he had not breached regulations and argued the test result meant he was “not under any subsequent legal requirement to self-isolate or quarantine”.
Ireland’s Department of Health has said a person is required to restrict their movements for 14 days if they arrive into Ireland from a country not on the green list.
It said the guidance does not state that a negative Covid-19 test shortens the 14-days requirement.
The leaders of the Republic of Ireland’s governing coalition had said the commissioner had clearly breached guidelines and he should have restricted his movement for 14 days.
Following news of the resignation, Taoiseach Micheál Martin, Tánaiste Leo Varadkar and Green Party leader Eamon Ryan said it was “the correct course of action given the circumstances of the past week”.
“We all have a responsibility to support and adhere to public health guidelines and regulations,” it continued.
European Commission president Ursula von der Leyen said she was grateful for Mr Hogan’s “tireless work as a trade commissioner”.
“He was a valuable and respected member of the college,” she said. “I wish him all the best for the future.”
Mr Hogan – who would have been leading the EU’s post-Brexit free trade negotiations with the UK – had been facing calls to quit in the wake of #GolfGate, as it has become known in Ireland.
The now infamous golf dinner was attended by a host of high-profile figures from Irish political life.
The controversy surrounding it has already cost the jobs of Agriculture Minister Dara Calleary and Jerry Buttimer, deputy chairman of the Irish senate.
The event took place the day after the Irish government changed its guidelines in the face of an increasing number of Covid-19 cases, with numbers allowed at indoor events cut from 50 to six, with some exceptions.
James Sweeney, from the Station House Hotel where the event was held, told RTÉ he had checked with the Irish Hotels Federation to ensure the event complied with regulations.
He said he was told it would be, if the guests were in two separate rooms, with fewer than 50 people in each.
Gardaí (Irish police) have said they are investigating what happened at the dinner.