The Queen used the wrong name for the Republic of Ireland when writing to president Patrick Hillery.
Despite all the diplomatic hoops that have to be jumped through when heads of state communicate, state papers released under the 30-year rule reveal a glaring error picked up by a senior civil servant and adviser on presidential affairs.
In extravagantly worded letters to President Hillery in 1983, the British royal marked the changing of the ambassadorial guard in Dublin.
In the note personally signed by the Queen, the royal confirmed the departure of Sir Leonard Clifford William Figg and in a follow-up note his replacement is confirmed as Alan Clowes-Goodison.
But Pat O'Sullivan, government secretariat in 1983 and adviser to Garrett FitzGerald on matters relating to the president, spotted a misnomer and asked for views of the Department of Foreign Affairs.
Despite the courtly language and tone of the diplomatic letters to President Hillery, the Queen had used "Irish Republic" rather than Republic of Ireland.
"We are Ourselves so satisfied with the zeal, ability, and fidelity with which Sir Leonard Figg has executed Our orders on all occasions during his Mission that We trust his conduct will also have merited Your approbation, and in this pleasing confidence We avail Ourselves of the opportunity to renew to You the assurances of Our constant friendship, and of Our earnest wishes for the welfare and prosperity of the Irish Republic," she wrote.
The 1948 Republic of Ireland Act, when the country formally became a republic with the president as head of state, declared that the state should be referred to as the Republic of Ireland.
The government secretariat twice raised concerns over the misnomer but there is no reference in the file as to whether Irish representatives wrote to Buckingham Palace or Downing Street over the error or whether it was resolved.