Diane Abbott has been fact-checked on social media after referring to King Charles by his former title.
The Hackney North and Stoke Newington MP shared a picture of Charles wearing a tie decorated with Greek flags at the Cop28 climate change summit.
The monarch sported the tie amid a diplomatic row between the UK and Greece over the Elgin Marbles.
Ms Abbott said on X/Twitter: “Look closely at the tie Prince Charles is wearing and it seems to have teeny tiny Greek flags all over it #ElginMarbles.”
But the former shadow home secretary, who sits as an independent after losing the Labour whip, mistakenly referred to the royal as Prince Charles despite him having been King for more than a year.
Ms Abbott was fact-checked by other users who added a note which read: “That is the King.”
Tory MP Brendan Clarke-Smith was among those pointing out Ms Abbott’s error.
He said: “He’s the King now, Diane.”
Charles wore the tie when he met Rishi Sunak just days after the Prime Minister snubbed his counterpart Kyriakos Mitsotakis in a spat over the Parthenon Sculptures.
Mr Sunak was due to meet Mr Mitsotakis at Downing Street last Tuesday.
But he cancelled the talks after the Greek Prime minister used an interview to demand the return of the Elgin Marbles.
Greece has long called for the historic works, which were removed by Lord Elgin from occupied Athens in the early 19th century when he was the British ambassador to the Ottoman Empire, to be handed back.
The King has close ties to Greece through his father Prince Philip, who was born on the Greek island of Corfu, to parents Prince Andrew of Greece and Princess Alice of Battenberg, before becoming a naturalised British subject in 1947.