The king’s moving homage came as the final master plan for the memorial for the nation’s longest-serving monarch was unveiled.
Referring to Elizabeth as “darling mama”, Charles, 77, said she had “remained constant, steadfast and wholly devoted to the people she served” throughout her long life.
The monarch died aged 96 in September 2022 after a 70-year reign.
“Much about the times we now live in, I suspect, may have troubled her deeply, but I take heart from her belief that goodness will always prevail and that a brighter dawn is never far from the horizon,” the king said in his message.
“For as a young Princess Elizabeth put it in her first ever public broadcast, aged just 14, we can each play our part ‘to make the world of tomorrow a better and happier place’.
“It is a belief which I share, with all my heart,” he added.
The memorial to the queen will feature a statue by sculptor Martin Jennings of her as a young woman dressed in ceremonial robes.
The bronze likeness will take inspiration from a celebrated 1955 portrait of her by Italian artist Pietro Annigoni.
A 28-year-old Elizabeth sat for Annigoni in late 1954 just a couple of years into her reign.
Robin Janvrin, Elizabeth’s former private secretary and chair of the memorial project’s committee, described the resulting portrait as a “lovely, iconic image of the young queen”.
The combined statue and plinth will stand 7.3 metres (24 feet) high at the entrance to the memorial in London’s St James’s Park, close to Buckingham Palace.
Unity bridge
The memorial will feature a family of gardens through the park with meandering paths and a new translucent glass-unity bridge, inspired by Elizabeth’s wedding tiara.
There will also be a smaller statue of her late husband Prince Philip dressed in his naval uniform looking up at his wife.
Charles and other members of the royal family will view maquettes of the planned statues and a scale model of the wider memorial on a visit to London’s British Museum on Tuesday.
Elizabeth, who was born on April 21, 1926 was not expected to become queen.
An accident of history brought her to the throne after her uncle Edward VIII abdicated in order to marry the twice-divorced American Wallis Simpson in 1936.
After the abdication her reluctant father, who suffered from a severe stammer, became King George VI.
But his death in 1952 saw the young princess accede, aged just 25, setting the stage for her record-breaking reign.
Since her death, the royal family have endured a turbulent time as a result of illness, family estrangement and scandal.
Both Charles and his daughter-in-law Catherine, wife of his elder son Prince William, have battled cancer, while his younger son Prince Harry wrote a wounding tell-all memoir after quitting royal duties with his wife, Meghan.
Charles’s brother Andrew, meanwhile, is facing a police probe amid new revelations about his ties to the late US sex offender Jeffrey Epstein.