At the service where King Charles gave his first speech to the country, no members of the Royal Family were present.
The Queen’s memorial ceremony at St. Paul’s Cathedral ended with the first formal performance of “God Save the King.”
The lyrics to the national anthem have changed from “Queen” to “King” and “her victorious” to “him victorious” to mark King Charles III taking over as the new monarch.
It comes after crowds spontaneously sang the version of the song outside Buckingham Palace on Friday as the King arrived with the Queen Consort Camilla.
The anthem is also expected to be sung at the Kia Oval cricket ground on Saturday as England and South Africa’s Third Test Match resumes. The match was paused on Friday following the Queen’s death.
No members of the Royal Family were present at the service but audio of King Charles’s first address to the nation was played to the congregation.
The King said he was speaking with “feelings of profound sorrow” as he told the country: “Queen Elizabeth was a life well lived; a promise with destiny kept and she is mourned most deeply in her passing. That promise of lifelong service I renew to you all today.”
King Charles went on to say: “As the Queen herself did with such unswerving devotion, I too now solemnly pledge myself, throughout the remaining time God grants me, to uphold the constitutional principles at the heart of our nation.
“And wherever you may live in the United Kingdom, or in the realms and territories across the world, and whatever may be your background or beliefs, I shall endeavor to serve you with loyalty, respect, and love, as I have throughout my life.”
Prime Minister Liz Truss and senior ministers were also in attendance along with 2,000 members of the public who collected wristbands on a first-come-first-serve basis.
Ms Truss, who met King Charles for a brief audience in person at Buckingham Palace earlier, gave a brief reading from the Bible.
She said: “We do not live to ourselves, and we do not die to ourselves. If we live, we live to the Lord, and if we die, we die to the Lord; so then, whether we live or whether we die, we are the Lord’s.”