Almost 1,000 people attended a tribute to the late Lady Jakobovits, during which a new charitable fund in her name was announced.
The Chief Rabbi Lord Sacks, Israeli ambassador Ron Prosor and Lady J's four daughters were among those to attend the service at St John's Wood Synagogue on Tuesday.
Simon Hochhauser, president of the United Synagogue, launched the Lady J Chesed Fund to develop the US's network of volunteers and create a new co-ordinator role focused on providing support to more isolated communities. Mr Hochhauser said: "Lady Jakobovits was the life of our community and she touched the lives of thousands of people through her acts of chesed [kindness].
"We at the United Synagogue, working through our local communities, believe passionately that we can continue her work by providing welfare for our members - many of whom are in real need."