“Suddenly you feel that he’s his own person,” said Barbara Lewis, a retiree from west London who was among several hundred mourners outside the cathedral.
The new king’s adult life has been lived in the shadow of his mother’s record-breaking reign, which encompassed a period of extraordinary change in Britain and around the world.
Her death has sparked heartfelt tributes from every corner of the globe.
Buckingham Palace revealed Charles and other members of the royal family would observe an extended mourning period from now until seven days after her funeral.
The date of the funeral, which will be attended by heads of state and government, has yet to be officially announced but is expected to be on Monday, September 19.
US President Joe Biden has said he will attend. The Kremlin said Russian President Vladimir Putin will not.
Her London palace has become a magnet for thousands of mourners, with flowers piling up in one of many poignant signs of the genuine reverence felt for her.
“She has been our monarch all my life,” said Joan Russell, a 55-year-old project manager from northeast London, tears running down her cheeks.
Leading two days of tributes to the queen in parliament, Truss -- only appointed by the late monarch on Tuesday, Sept.6 -- offered the nation’s support to Charles as she acknowledged the “awesome responsibility” now upon him.