Chief Rabbi Ephraim Mirvis was unable to deliver his eulogy at the funeral of Rabbi Lord Sacks because he has been instructed to self-isolate.
Instead, Rabbi Mordechai Ginsbury, of Hendon United Synagogue, delivered the hesped prepared by Rabbi Mirvis for Sunday's levaya.
The Chief Rabbi began his eulogy by writing: "I am truly sorry that having been instructed by my NHS app to self-isolate, I am not able to be here in person."
A message on The Office of Rabbi Sacks YouTube page also said: "This video is of a hesped (eulogy) by Chief Rabbi Ephraim Mirvis who was unable to attend in person due to UK Government COVID restrictions."
The Chief Rabbi added he was "grateful" to Rabbi Ginsbury for reading the hesped.
During his eulogy, Rabbi Mirvis said: "Mere words cannot do justice to Rabbi Sacks contribution to this world." He described him as a "remarkable spiritual leader, educator, author, broadcaster and mentor.
"An outstanding ambassador for Judaism."
Rabbi Mirvis wrote it was "difficult if not impossible to think of Rabbi Sacks in the past tense."
The Chief Rabbi's spokesperson confirmed he was "saddened" not to be able to deliver his hesped at the funeral.
He said Rabbi Mirvis was in "very good health" but was careful to abide by the official Covid-19 regulations.