“I’ve made this point before so when this speaker came on I felt uncomfortable, and I decided it was no longer appropriate for me to remain in the shul that day. So my family and I left.”
The JC understands Mr Lewis and his family were the only congregants to leave the service.
The Saatchi Shul, formerly an independent congregation, is based in St John’s Wood in North West London.
Rabbi Mendel Cohen, the synagogue’s minister, said: “At the Saatchi Shul we pride ourselves as an open congregation that welcomes individuals from across the community with a wide range of opinions. We also welcome a variety of speakers from across the social and political spectrum.
“Our speaker last Shabbat offered a unique angle. He appears frequently in the New York Times and on CNN.
“While politics can inspire strong reactions, we never seek to offend. Indeed, Saatchi Shul is known for being a very personal community.”
Prof Rosenbaum frequently focuses on topics such as justice, Israel and Islam. In an address at an American shul in 2015, he claimed that “there is no compromise in the Muslim mindset”.