Niall Burgess, who was secretary general of the department of foreign affairs (DFA) at the time, tweeted a selfie on 17 June 2020 showing a group of officials in the department's Iveagh House headquarters celebrating Ireland's election to the UN Security Council.

The picture - captioned "now we're walking on air…" - showed a tightly-gathered group of around 20 people, with champagne bottles and glasses visible, but was deleted a short time later.

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What were Ireland's rules at the time - and how were they broken?

Ireland's lockdown rules meant indoor gatherings of more than six people were banned.

People were urged to work from home where possible, and physical distancing and face mask guidance was in place.

An internal DFA report into the event, published last night, found a "serious breach" of social distancing rules had occurred at the gathering, which "caused offence, inflicted reputational damage on the Department and undermined internal morale".

The report stated that Mr Burgess was found to be "largely responsible for facilitating the breach of social distance guidance that occurred".

It recommended that he pay €2,000 (£1,670) to a charity providing assistance to people affected by COVID, and that the three other senior officials visible in the photograph donate €1,000 (£835).

All have agreed to do so, and the report added that no further action would be taken.

The review also concluded that the event was not organised or pre-planned, and that the staff gathered at Iveagh House were "conducting essential business".

What's the reaction been?

The minister for foreign affairs, Simon Coveney, said the report was "fair and balanced", and described the gathering as a moment of careless celebration that only lasted for around a minute.

But Sinn Fein has called for an independent investigation.

The party's finance spokesperson Pearse Doherty said that "there is no accountability in this report, and an internal investigation was never going to provide it".

"It is clear that an independent investigation is the only way to get to the bottom of this," he said.

"Sinn Fein have already communicated this to the Taoiseach [Irish Prime Minister Micheal Martin] in a letter last week. It is now up to him to act."