Royal aides drew up secret plans to make Charles the first regent since 1820 and step in during the final years of the Queen’s reign

Palace aides drew up secret plans for Prince Charles to become regent and replace the Queen during the final years of her reign, The Mail on Sunday can reveal.

The proposals – which have never been reported before – include soft “regency light” and “reversible regency strategies” if his mother were to become “incapacitated.”

If this were activated, Charles would have been the first regent since 1820 – when George III’s eldest son stood in his place.

Buckingham Palace played down such plans when the queen was alive, with aides pointing to the promise she made on her 21st birthday to serve until her death. Charles himself proved reluctant to participate.

But compelling detail in a new biography of the king by The Mail’s Royal expert Robert Hardman reveals that aides worried about how long the Queen would rule ‘long before’ she became visibly weak, with courtiers ‘seriously considering’ about the prospect of regency.

Buckingham Palace played down such plans when the queen was alive, with aides pointing to the promise she made on her 21st birthday to serve until her death

Details of the plans have been made public for the first time in the new book Charles III: New King. New Court. The Inside Story, which is broadcast exclusively by the Mail and The Mail on Sunday.

Other extraordinary details in today’s excerpts reveal:

• How King Charles refused to undermine his mother in her final years by engaging in detailed plans for his accession;
• The government secretly feared civil unrest after the queen’s death;
• King Charles and Prince William had a private summit at Birkhall – without Prince Harry – on the night the Queen died;
• The next day, a well-wisher hugged the new king outside Buckingham Palace, breaking with tradition and signaling Charles’ more relaxed monarchy style;
• Queen Camilla cried during Charles’ televised address to the nation and feared she would “confuse him”;
• How the crowds were so great during the Queen’s final six-hour tour of Scotland that there was only one short stretch where the Princess Royal (in the car behind her) could grab a drink and a snack;
• Behind the scenes, aides viewed a regency as “almost inevitable” if the queen had reached the same age as her mother, who died at the age of 101.

Robert Hardman reveals aides worried about how long the Queen would rule ‘long before’ she became visibly weak, with courtiers ‘seriously considering’ the prospect of a regency

Palace officials prepared for the queen’s slow decline or a “sudden public collapse.”

The options include minimal involvement, called “regency-light,” and a temporary replacement for a short-term disability, called “reversible regency.”

An ex-private secretary to King Charles, Sir Stephen Lamport, who resigned in 2002, was even recalled from his career in the city to work on the blueprints.

But Charles was ‘extremely’ reluctant to talk about the regency because he did not want to ‘tempt fate’ or ‘dwell on the details’.

Any plans that might involve him tracking down his mother would be subject to the ‘Henry V test’, referring to Shakespeare’s epic which depicted a prince jostling to steal the Crown. This meant that it was only as the Queen approached her 90th birthday in 2016 that aides began to seriously consider Charles’ coronation.

A year earlier, Charles’ private secretary, Sir Clive Alderton, had filmed a rehearsal of the Accession Council – a ritual for becoming monarch.

The new king watched the video on the night the queen died with Prince William. Prince Harry – who would have been automatically invited in previous years – was not present.