Saturday 29th of June 1946 has been given the title “Black Saturday”, because on that day the British began an extensive operation against the Yishuv named “Operation Agatha”. A curfew was imposed on many cities; house to house searches were made and a few of the Yishuv leaders were arrested. The purpose of this operation was to impair the power of the "Jewish Resistance Movement” (Tnu’at HaMeri HaIvri). This movement carried out attacks against British troops and officials, the most prominent of which was the “Night of the Bridges”.
“Operation Agatha” was carefully planned, but the details leaked to the Haganah organization. Consequently, the leaders of the Yishuv received an advance warning and managed to escape before the British soldiers arrived. Some of their weaponry was transferred to alternative hiding places. The Haganah Command broadcast the details of the plan on its radio station, “Kol Yisrael”, hoping that the operation would be cancelled once it had been exposed, but the British carried it out nevertheless.
British forces invaded the building of the Jewish Agency in Jerusalem. They arrested the management members: Moshe Sharett, Yitzhak Gruenbaum, Dov Yosef, David Remez and Yehuda Leib Maimon, and transferred them to Latrun detention camp. David Ben-Gurion stayed in Europe at the time and didn’t get arrested. The British confiscated documents and files from the Jewish Agency building. The documentation proved that the Jewish Agency took a central role in “The Jewish Resistance Movement”.
The British soldiers searched for weapons in various settlements. Kibbutz Yagur suffered great damage due to a thorough scan the British did, probably because they had prior information about caches in the Kibbutz. At Kibbutz Mizra, the British confiscated documents of the Palmach, including their encrypted card index which they failed to decrypt.
17,000 British soldiers took part at this operation, and more than 2,700 individuals were arrested and transferred to detention camp in Atlit and Latrun.