A newspaper letter signed by leaders of the UK’s two Progressive movements and the leading Jewish interfaith activist, revealed growing unease within the community over Israel’s military campaign.

Published in the Observer, it voiced concern that Israel’s actions could “strengthen extremists” while civilian casualties threatened to “undermine international support for Israel”.

Its 11 signatories included Rabbi Dr Tony Bayfield, of the Reform movement; Rabbi Danny Rich, of Liberal Judaism; Sir Sigmund Sternberg; Baroness Neuberger; Rabbi Professor Marc Saperstein, of the Leo Baeck College; and members of Peace Now UK.

Rabbi Rich said that, while the Liberal movement supported Sunday’s solidarity rally, its intended tone was “not one I subscribed to. If it had been standing with Israel in support of a ceasefire, I would have gone along.”

He addressed an audience of Muslims in Yorkshire. “My son has come back from Israel and wants to go back to join the army. My best friend lives in Haifa. I am not saying this is easy.”

Meanwhile, 78 people “of Jewish origin” signed a letter in the Guardian on Saturday comparing Israel’s actions to the Nazis in the Warsaw Ghetto. And Jews for Justice for Palestinians placed a full-page advert in Wednesday’s Times headed “Stop the Slaughter”.