It is 20 years since the last Lubavitcher Rebbe, Menachem Mendel Schneerson, died. But the outreach enterprise he launched continues to flourish with 3,000 centres and 4,000 emissaries in around 80 countries.
On Tuesday night, its British branch attracted a record attendance to its dinner at a Mayfair hotel, with many new faces among the 560 guests. "We have a new army of supporters," said Chabad Lubavitch UK chief executive Rabbi Bentzi Sudak.
But there were also many longstanding friends. Barry Prince, of Hadley Wood Synagogue, who has backed the movement for 20 years, said it represented "the best in Judaism because they are non-judgmental".
Lord Sacks - who attributes his choice of a rabbinic career to his encounter with the Rebbe as a student - made one of his rare speeches at a home function since his retirement as Chief Rabbi a year ago.
"We see a world filled with hatred and violence and death. That can lead us to very dark thoughts and dark places," he said. "The Rebbe taught us you can change the world if we bring the same passion, intensity and energy to love, to peace and to life.
"Think of another rabbi in a thousand years who changed every single Jewish community in the world and places where nobody ever dreamt there would be a Jewish community."
With a £4 million budget, the UK movement has grown to 25 community Chabad houses, 11 campus houses and 14 schools.
Rabbi Sudak outlined plans to build a boys' high school and to expand work with young adults, particularly post-university.
He recalled "a fourth-year student at Nottingham University who met Chabad in the street because of our menorah. Until then, he had not realised there were other Jews in Nottingham - and Nottingham has 1,000 Jewish students."
The dinner also highlighted the achievements of his late father, Rabbi Nachman Sudak, principal of the foundation, who was sent here as an emissary by the Rebbe in 1959 at the age of 23.
Guest of honour was London-based Ukrainian philanthropist Gennadiy Bogolyubov, sponsor of the largest Jewish community centre in the world, in Dnepropetrovsk, and founder of a new community in Belgravia.
Referring to the conflict in Ukraine, Rabbi Sacks said that "while others are fighting political and military battles, Gennadiy is making possible the most extraordinary spiritual victory for Jewish life in Ukraine."
Rabbi Sudak said that when Lubavitch had faced problems in Britain a few years ago, Mr Bogolyubov "reached out to me and said, 'I want to help you'."