During the British Mandate for Palestine from 1920 until 1948, the de facto flag was the Union Flag

Union Flag

The Union Flag, also known as the Union Jack, is the flag of the United Kingdom. It retains an official or semi-official status in some Commonwealth Realms; for example, it is known as the Royal Union Flag in Canada. It is also used as an official flag in some of the smaller British overseas...

 or Union Jack of the United Kingdom, but several localized flags existed for Mandate government departments and government officials. The only Palestine-specific flag not restricted to official government use was the Palestine ensign (red with the Union Flag in the canton

Canton (heraldry)

Canton is a square charge placed in the upper dexter corner. It is classed by some heraldic writers as one of the honorable ordinaries; but, strictly speaking, it is a diminutive of the Quarter, being two-thirds the area of that ordinary. However, in the roll of Henry III the quarter appears in...

, and a white circle on the fly with the mandate's name inside it), which was flown by ships registered in the British Mandate territory during the period 1927–1948. This flag had an extremely limited use on land, and was not embraced by either the Arab

Arab

Arab people, also known as Arabs , are a panethnicity primarily living in the Arab world, which is located in Western Asia and North Africa. They are identified as such on one or more of genealogical, linguistic, or cultural grounds, with tribal affiliations, and intra-tribal relationships playing...

s or the Jews of the Palestine mandate territory. It was based on the British Red Ensign

Red Ensign

The Red Ensign or "Red Duster" is a flag that originated in the early 17th century as a British ensign flown by the Royal Navy and later specifically by British merchantmen. The precise date of its first appearance is not known, but surviving receipts indicate that the Navy was paying to have such...

 (civil ensign) instead of the Blue Ensign

Blue Ensign

The Blue Ensign is a flag, one of several British ensigns, used by certain organisations or territories associated with the United Kingdom. It is used either plain, or defaced with a badge or other emblem....

 (used as the basis for the flags of nearly all other British-ruled territories in Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 and Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

), since it was only intended for use at sea by non-government ships.