Page 139 - ISRAEL'S CRADLE

At the same time, and particularly on Sunday morning, the details of the comprehensive British operation in Jerusalem and the other parts of the Land of Israel were revealed. In Tel Aviv, the British also raided the "National Institutions" offices and also added to their list entities such as "Hapoel," Bank Hapoalim and even WIZO. In one of the cases, they also broke into a British office, apologized and left. Hungry soldiers had apparently broken into stores and even kiosks.
In Haifa, several leaders of the Histadrut were arrested and transferred to Latrun for detention. Most of the searches were conducted in the working settlement farms. Military forces surrounded dozens of kibbutzim including Ein Harod, Tel Yosef, Beit HaShita, Gvat, Mizra, Afikim, Sdot Yam, Na'an, Givat Brenner and Ramat Rachel. Thousands of detainees were led to the Atlit and Latrun detention camps and afterwards to the special detention camp that was established in Rafah. A particularly broad search was conducted in Kibbutz Yagur near Haifa, and over an entire week the British had basically taken the kibbutz apart and also found "Slikim" (hidden weapons caches) of the "Haganah" with particularly large amounts of weapons and ammunition. This was the only settlement in which weapons of the "Haganah" were discovered.
Getting back to the National Institutions Building, here too the British searched not only for documents but rather for more incriminating findings. It turns out they had informants on the inside, yet they apparently did not know all the secrets. For example, they did not know the location from which the Jewish Agency was broadcasting to its offices overseas, nor the location of several Slikim in the building.
One Slik was in the generator room in the building's basement and another Slik was in the large meeting hall. It turns out that some of the particularly confidential documents were hidden within the frames of the portraits of Weizmann and Herzl, but the British did not suspect the portraits and did not look for what was hiding behind them. Some estimate that there are additional Slikim throughout the building that have not been discovered to this day.
And there was also a tunnel that led from the building to the other side of King George Street, which was intended for escape in an emergency. It was only discovered decades later and the British did not discover it either.
The activities of the National Institutions did not cease even when the office building was occupied by the British. The members of the Jewish Agency management who were not arrested, Eliyahu Dobkin and Emil Schmorak, met daily and discussed current events, and were in regular contact with the most senior member of the Executive, Moshe Shertok, even when he was detained in Latrun. They found ways to maintain constant communication with him and with Ben-Gurion in Paris. Shertok passed notes through his wife Tzipora, both to Dobkin and Schmorak in Jerusalem and to Ben-Gurion overseas.
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