The lyrics to the national anthem have changed from “Queen” to “King” and “her victorious” to “him victorious” to mark that King Charles III has now taken over as the new monarch.
It comes after crowds spontaneously sang the version of the song outside of Buckingham Palace on Friday as the King arrived with the Queen Consort.
The anthem is also expected to be sung at the Kia Oval on Saturday as the England v South Africa Third Test Match resumes. The match was paused on Friday following the Queen’s death.
Members of the royal family did not attend the 6pm service at St Paul’s, in London, which was open to the public and was broadcast live by the BBC.
However, an audio of the King’s televised address to the nation was played inside the cathedral.
Within the message, which was also broadcast on television, he paid tribute to his “darling mama”, and said: “And to my darling Mama, as you begin your last great journey to join my dear late Papa, I want simply to say this: thank you.
“Thank you for your love and devotion to our family and to the family of nations you have served so diligently all these year.
“May ‘flights of Angels sing thee to thy rest’.”
A total of 2,000 seats were allocated to the public on a first-come-first-served basis, with all of the wristbands for the evening service being distributed within three hours, a cathedral spokeswoman said.
Ahead of the service, a hundreds-strong queue formed, winding from St Paul’s to beyond the Tube station streets away.
Attendees were dressed smartly in black suits and ties while others wore black mourning veils as they waited to take their seat inside the cathedral.
They remained quiet throughout the service, with one woman using a handkerchief to wipe tears away from her eyes as she sat in the pews.
New Prime Minister Liz Truss also attended the service, and remained solemn as she gave a Bible reading from Romans 14.7-12.
Several politicians were also in attendance, including London Mayor Sadiq Khan, Labour leader Sir Keir Starmer, Chancellor Kwasi Kwarteng, Foreign Secretary James Cleverly, the Speaker of the House of Commons and the Lord Speaker.
Deputy Prime Minister Therese Coffey, Leader of the Commons Penny Mordaunt and Welsh Secretary Robert Buckland were all seen standing together and singing along to a hymn during the service.
Dame Sarah Mullally, Bishop of London, as Dean of the Chapels Royal, delivered the address, while Archbishop of Canterbury Justin Welby gave the blessing.
Music included Behold O God Our Defender, Bring Us, O Lord God, At Our Last Awakening, and Nunc Dimittis from Evening Service in G.
Hymns included All My Hope On God Is Founded, O Thou Who Camest From Above, and The Lord’s My Shepherd.