His Holiness Pope Benedict XVI announced it through the Vatican, to shock and surprise.
A poised Queen Beatrix of the Netherlands revealed it in a video uploaded to YouTube, and King Juan Carlos of Spain confirmed it by signing a parliamentary bill.
Queen Elizabeth, however, has vowed that abdicate is something she will never do.
Abdication is, after all, a dirty word in the corridors of Royal palaces, especially after the earthquake caused when her uncle Edward VIII quit the throne in 1936 to marry the twice-divorced Wallis Simpson.
And there is no indication that that will ever change.
Yet with the Queen now into her 92nd year, and with the hard-working Duke of Edinburgh choosing to retire last month at the age of 96, plans are afoot which, if implemented, would see Charles appointed King in all but name.
Palace sources have indicated that the Queen has told her inner circle that, if she is still on the throne at the age of 95, she will ask for a piece of legislation called the Regency Act to come into force – granting her eldest son full power to reign even while she still lives.
The Queen now into her 92nd year, and with the hard-working Duke of Edinburgh choosing to retire last month at the age of 96, plans are afoot which, if implemented, would see Charles appointed King in all but name
I have spoken to a number of high-ranking courtiers who made it clear that preparations for a transition are moving ahead at pace. They have all confirmed that a Regency with Charles taking the lead is now, at the very least, a real possibility.
One senior former member of the Royal Household said: ‘Out of the profound respect the Queen holds for the institution of monarchy and its stewardship, Her Majesty would want to make sure that she has done everything she can for her country and her people before she hands over. She is dutiful to her core.
‘Her Majesty is mindful of her age and wants to make sure when the time comes, the transition of the Crown is seamless.
‘I understand the Queen has given the matter considerable thought and believes that, if she is still alive at 95, she will seriously consider passing the reign to Charles.’
High-ranking courtiers have all confirmed that a Regency with Charles taking the lead is now, at the very least, a real possibility
Clarence House – the household of Prince Charles – is making no comment about Plan Regency, as it has been called. However, it is understood to be a matter of increasingly open discussion at court.
But Palace staff responsible for communications have been ordered to be ‘up to speed’ on the 1937 Regency Act, which grants power to the heir apparent ‘in the event of the incapacity of the Sovereign through illness, and for the performance of certain of the Royal functions in the name and on behalf of the Sovereign in certain other events’.
The development is all the more significant as it comes against the backdrop of momentous shifts at court – a series of senior staff changes and departures at Buckingham Palace and Kensington Palace, home to the young Royals.
The Queen’s Private Secretary, Sir Christopher Geidt, 55, resigned his position two weeks ago, sparking turmoil and a ‘wholesale regime change’ – as revealed in The Mail on Sunday.
His shrewd deputy – former banker, political adviser and television executive Edward Young, 50 – will replace Sir Christopher after a suitable handover period.
I understand that a number of other high-profile figures – many loyal to Sir Christopher – are poised to leave the Royal Households at Buckingham Palace and Kensington Palace after his unexpected exit.
They include Assistant Private Secretary Samantha Cohen, the capable former Press Secretary and Sir Christopher’s number three in the private office. Ms Cohen, who is Australian, is said to be a firm favourite with the Queen.
Affectionately known as Prinny, the future George IV, was notorious for his hedonism
The last Prince Regent was appointed in 1811 after George III suffered episodes of mental illness and his eldest son was asked to take over his duties.
Affectionately known as Prinny, the future George IV, was notorious for his hedonism – drinking, eating to excess and keeping several mistresses at once.
The Regency, which lasted until his father’s death in 1820, was tumultuous.
Prime Minister Spencer Perceval was assassinated in 1812 and, with the Napoleonic Wars raging, taxpayers were riled by the Regent’s spending.
His failed attempts at