Number 10 has since edited the Instagram post to remove all reference to the flag for the Republic of Ireland.

The initial post read: "Yesterday we celebrated the culture of Northern Ireland with a reception in Downing Street.

"Businesses from across Northern Ireland arrived to showcase some of the best produce the country has to offer."

Politics news - latest: Chief medical officer makes lockdown admission

Asked about the post today, the prime minister's official spokesperson admitted it was an "unfortunate mistake that was corrected".

David Blevins, Sky News' senior Ireland correspondent, was critical of the mistake, writing on X: "10 days ago, I said we had a home secretary who didn't know the difference between Unionists and Nationalists.

"She wasn't alone. Number 10 doesn't know the difference between Ireland and Northern Ireland."

Suella Braverman, the former home secretary, was criticised for using "inflammatory" language in an article for The Times before her sacking.

She again described pro-Palestinian protesters as "hate marchers" and added: "I do not believe that these marches are merely a cry for help for Gaza.

"They are an assertion of primacy by certain groups - particularly Islamists - of the kind we are more used to seeing in Northern Ireland."

One former Tory cabinet minister told Sky's political editor Beth Rigby at the time Ms Braverman's comments were "wholly offensive and ignorant of where people in Northern Ireland stand on the issues of Israel and Gaza".

"It would be good to know what she knows about what Northern Ireland people think about the current Israel-Palestine situation before she casts aspersions," they said.

Read more: Suella Braverman has displayed breathtaking ignorance on Northern Ireland

Northern Ireland has not had a functioning government since February 2022 after the Democratic Unionist Party (DUP) refused to form a power-sharing government in protest over post-Brexit trading arrangements.

In February this year, Rishi Sunak negotiated a new deal for Northern Ireland called the Windsor Framework, aimed at addressing the difficulties caused by the controversial Northern Ireland Protocol.

But the DUP has argued that problems remain and the new Windsor Framework still leaves the nation subject to EU rules, something it opposes.