Writing for the Daily Mail, columnist Robert Hardman said the order was “a strong hint” that Camilla could be named Queen rather than Princess Consort.
The official position of the Firm is that the duchess will be styled the Princess Consort when Charles ascends to the throne, a position agreed after her 2005 wedding to the Prince of Wales.
Mr Hardman writes: “It is an increasingly incongruous title given that the wife of a King is always Queen.
“The Royal Family do not want to go near this subject since it invokes memories of the prince’s divorce from Diana and the dark days after her death.
“It is an issue for another day.
“This honour, though, makes it pretty clear what the current Monarch thinks.”
The Garter was created by King Edward III in 1348 and is an accolade awarded by the sovereign for outstanding public service and achievement.
Camilla’s appointment was a gift from the monarch and was made without Prime Ministerial advice.
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