The decision to deport the underground members to Africa was made by the British following the radicalization of their activities and the recommendation of the chief secretary, substitute of the High Commissioner, John Shaw.
The undergrounds reacted strongly and denounced the deportation, and intended to carry out an armed struggle to force the Mandatory government to return the deportees.
Irgun men, headed by Aryeh Ben-Eliezer, appealed to the Supreme Court which accepted their claims in part, noting that the rendition was unauthorized, but that the arrest was nevertheless legitimate, since it was enforced by a warrant from the Eritrean government.
The conditions in the Sembel camp were not inferior to the ones in Latroun, despite the lack of many means of convenience, from books to clothes and toothbrushes.
A mutinous act by the detainees, in which they demolished a wall to cover the drainage finally convinced the camp commander to improve their conditions.
The British encouraged extensive educational activity, including language classes by detainee Uzzi Ornan.
The Yishuv was infuriated, and demanded the appointment of an inquiry committee, but the British army insisted that the guards behaved correctly.
Rabbi Yitzhak HaLevi Herzog was eventually sent to the camp as moderator, and his activity was more satisfactory to the British than the detainees.
American Zionist activists persuaded International Committee of the Red Cross to intervene on the detainees behalf, and, unwilling to rebuff a request from such an esteemed organization, the British Colonial Office allowed a Red Cross official to visit a detention facility in Eritrea in June 1946.
The dry climate and high altitude was causing anxiety and insomnia, which in turn led to chronic heart and pulmonary problems.
Three men, including Yitzhak Shamir[6] and Yaakov Meridor, who was so eager to escape he did not try to use his senior position in the Irgun to become a leader in the camp, tried to hide in water tanks and bribe the Sudanese driver transporting them.
The certificates finally aroused the suspicion of a train conductor in Khartoum, who called the security service, which caught them six days after their escape.
The Ethiopian emperor, Haile Selassie was pressured by the British as well as Jews, and eventually agreed to turn them in, perhaps in exchange for an imprisoned family member.
The fourth escapee, Eliyahu Lankin, who further utilized local Jews, was jailed in Addis Ababa, but was released thanks to interceding with the emperor.
The sixth attempt, in September 1946 in Sembel, once again included Meridor and another Irgun man, was made by breaking holes in the ceilings.
On arrival, they were anticipated by British policemen, but the French were reluctant to turn them in, and they used fabricated South American certificates to demand their release.
The other three were returned to the camp in August 1947, after a long hiding period in Addis Ababa and just before boarding a plane chartered by Irgun supporters to get them to Paris.
Using improvised printing machines and the Larousse Encyclopedia, El Salvador and Honduras passports were forged, complete with replications of their symbols.
Unaware of the fact that the escapees were already safely in Europe, the British authorities in Eritrea launched searches for them in Kenya.
The reason given was the need for keeping the truce rules, which included banning the entrance of young men eligible for military service.
Despite the Altalena affair, the Israeli authorities expressed an unequivocal support of their return, although Moshe Sharett did not rule out the option of arresting them immediately on arrival, fearing that they might subvert the government.