Haapalah / Aliyah Bet

In 1913, Shaul's father, Yehuda Meirov, joined the family, and they settled in Tel Aviv.

In 1940, Shaul Meirov and Reuven Shiloah were instrumental in forming SHAI ש"י‎, שירות ידיעות‎, the intelligence/information wing of the Haganah הגנה.
Until 1948, SHAI ש"י's primary objectives were:
* promoting of an independent Israeli state
* infiltrating British mandate offices in order to inform the Jewish and Zionist leadership of British attitudes and proposed actions
* collecting political information that could be used as propaganda
* penetrating Arab and anti-Zionist factions in Palestine and abroad
* providing security for the arms-smuggling and illegal immigration programmes of the Haganah הגנה.

In 1922, Shaul Meirov מאירוב‎ was chosen to serve on the Central Committee of the Haganah.
Berl Katznelson and Eliyahu Golomb asked him to served as Member of the National Command; where he had two functions: a security role - as the "armory coordinator" of the Jewish settlements in the Galilee - and a semi-political role, as a participant in opposition to the HaShomer organization and their leader, Yisrael Shohat, who were opposed to operating under the command of the Histadrut haOvdim haClalit and the Haganah's leadership.
Arieh Boaz cites: "Many regarded Shaul as `Eliyahu's representative' in the Hagana and as a loyal advocate of Golomb's philosophy and outlook."
He ws the founder of Shai ש"י‎, Israeli Inteligence Service; Resh Nun Rigul Negdi, the counter intelligence service; Taas תע"ש. clandestine military industries; and Head of Mossad leAliyah Bet, and was responsible for arms procurement in Europe.

In March, 1942, Shaul Avigur went to Baghdad to investigate the potential of the Shabab al-Inqad, who were interested in making contact with Palestine and exploring the possibility of emigration, to work on behalf of the yishuv in Palestine, and found them sufficiently well-organized.

In December, 1943, Shaul Meirov went to Izmir and complete arrangements for transport of the Greek Jews hiding in that city.
Rafae Barki arranged a meeting between Thomas, Shaul Meirov, and the Commander of the Greek boats, in which it was decided that the partisans would receive food, clothing and medicine in exchange for the transport of the refugees.
At the arrival of each group, Shaul Meirov, or his man in Izmir, would take their documents to Istanbul to obtain Palestine visas from the British.
The refugees were taken care of by the Jewish community until the date of their departure for Palestine.

In 1944, Shaul Meirov returned to Izmir, and appointed Moshe Auerbuch Agami to direct the job in his place.
When he finished his work in Turkey, Moshe Auerbuch Agami was transferred to Romania.

Arieh Boaz cites: "Shaul [Avigur] was regarded as one of those individuals whose very personality constituted ethical authority. Those who worked with him accepted his authority as something that was self-understood, even when they did not see eye to eye with him on some of his decisions or even when his decisions were difficult to put into practice. The reason why they accepted his authority was that they clearly comprehended that Shaul's decisions and demands invariably stemmed from an approach that was totally committed to a set of lofty values and which was neither biased nor in the service of personal interests."

In November, 1946, Ruth Chaikin was sent to France on SS Transylvania.

In November, 1946, Shaul Meirov Avigur sailed on SS Transylvania, with false papers, along with nine Palmachnikim, who boarded as stowaways, and were quickly discovered at sea, and were locked in a hold and badly beaten up, during the voyage, which lasted seven days.
Ruth Cheikin served as a go-between between the prisoners and Shaul Meirov Avigur, and later to a member of the Recanati family who was on the ship on his honeymoon.
They all went to the refugee camp near Marseille.

Shaul Meirov and Nachum Carmeli prepared Yilderim haBarak הברק in Marseille, for her voyage.

MI6, despite the covert operations and efforts made to evade detection, became aware of Pan Crescent פאן קרסצנט, and the substantial refitting carried out in Venezia, to accommodate the anticipated 7,500 passengers.
British Government Communications Headquarters (GCHQ), working with with the American National Security Agency (NSA), spotted the transaction for the ship's purchase in the United States, and followed the operation, planning to stop her voyage, and her lmission.
Harold Perkins, a senior MI6 officer, devised the plan to sabotage the ships, and the Kent Corps Specials, headed by Fredrick Vanden Heuval, were assigned to destroy Pan Crescent at its berth.
Posing as smugglers, the team of Kent Corps Specials approached the vessel in a small boat, attached mines to her hull beneath the waterline, and rowed away.
Pan Crescent פאן קרסצנט did not sink after the mine detonated, due to quick action of those on board, who immediately manned the pumps, and luckily, the sabotage took place in shallow waters, rather than on the open sea.
Palyam sent Motti Hod and Haim Winkler, to investigate the explosion, and they found the Italian foreman who had collaborated with the British Intelligence; he confessed that had saved the ship by shortening the detonator fuse, so that the mine would explode in port, rather than on the open sea.
Shaul Meirov, who was in Switzerland, decided not to scrap the mission, ordered Pan Crescent פאן קרסצנט be repaired.
The hole from the explosion was temporarily blocked, and Pan Crescent פאן קרסצנט was towed the shipyard where it was properly repaired.
Shaul Meirov cites another attempt to sabotage was made when “..a mysterious fire caught on the motor room which was hardly extinguished.”

Yehiel Duvdevani cites: "We regarded Shaul [Avigur ]as the conscience of the ["illegal" immigration] organization, as an individual whose every move was in conformity with a highly-principled conscience."