LONDON, Feb 2 (Reuters) - Queen Elizabeth fears that Britain will be shocked by the different style of monarchy Prince Charles is planning, according to a new biography of her heir apparent.
'Charles: The Heart of a King' claims that the 66-year-old prince's passion for embracing sometimes unusual causes has prompted disquiet at Buckingham Palace, where Elizabeth, 88, is set to overtake Queen Victoria in September as Britain's longest reigning monarch.
When his turn finally comes to ascend the throne, Charles plans a new model of kingship that would create a smaller monarchy and open up royal residences to the public, according to the biography.
"In the corridors and back rooms and private apartments of Buckingham Palace there is mounting anxiety as the Queen's reign enters what an insider calls 'its inevitable twilight'," according to Catherine Mayer, the author of the biography, which has been serialised in the Times newspaper.
"In defining his role as heir apparent, the prince has signalled a redefinition of the monarchy. Some courtiers - and the sovereign herself - fear that neither the Crown nor its subjects will tolerate the shock of the new."
Charles's father, the Duke of Edinburgh, is among his harshest critics, the book claims, and believes the prince to be guilty of "selfish behaviour" in putting his "cerebral passions" before his royal duties.
Charles himself is quoted by the author as saying: "I only take on the most difficult challenges... I want to raise aspirations and re-create hope from hopelessness and health from deprivation."
A spokeswoman for Buckingham Palace declined to comment on the book, but a spokeswoman for the Prince of Wales released a detailed statement, saying Mayer had not been given exclusive access to the prince and emphasising that her book was not an official biography.
In a rare comment on the kind of king Charles would be, the spokeswoman said:
"He is often described as being ahead of his time. The evidence for this has been well documented and includes leading the work on corporate social responsibility, from as early as the 1980's, demonstrating the benefits of organic farming, as well as finding ways to help young people who are not in employment."
"Speculation about The Prince of Wales's future role as King has been around for decades but it is not something we have commented on and nor will we do so now," she said.
The eldest son of Queen Elizabeth and groomed from birth to one day be king, Charles has taken on the responsibilities of public life but found himself for years eclipsed by Princess Diana, his first wife who died in a Paris car crash in 1997.
In 2005 Charles married Camilla Parker Bowles, who will one day sit alongside him as queen according to the current assumption in Buckingham Palace, Mayer wrote. (Writing by Guy Faulconbridge; Editing by Sophie Walker)