The British favor a Jewish homeland in Palestine (Balfour Declaration) and Jewish immigration increases, so to does the confiscation by Jewish settlers of Palestinian land, alarming the Palestine Arab population -who had been promised by the British an independant Arab state at the end of WW1.
1937, Peel Commission finds the British promises to both Arabs and Jews irreconcilable, declare it's Mandate unworkable, and recommend partition of Palestine into Arab, Jewish and British sectors.
Riots erupt and terror attacks increase from both sides.
The British, after securing their oil interests in Iraq, and the Suez Canal in Egypt, drop the Palestine issue like a hot potato.
Haganah, Irgun, and the Stern Gang emerge as Jewish terrorist groups. Irgun, led by Menachen Begin, announce in 1944 a war against the Mandate and intention to assassinate all British officials who limit Jewish immigration. Most Israeli leaders then, as now were members or supporters of these Jewish terrorist organisations.
1947, a Conference in London with British, Arabs and Zionists produce no agreement. Britain declares it will leave Palestine the following year (May 14), handing the unresolved dispute to the UN.
The UN adopts a plan for the partition of Palestine into Arab and Jewish states, Jerusalem to be under UN administration. Jaffa to be Arab, Tel Aviv to be Jewish.
Arabs throughout the Middle East reject the plan, the Jews prepare for war.
In 1948 Britain exits, and Israel declares its independance. Egypt, Jordan, Iraq, Syria and Lebanon mobilise for war, and invade the one-day old state.
The UN plan is out the window, like so many agreements and plans that are to follow.
The Arab armies advance, and Israel resist, and after 10 days were able to counterattack, repulsing the Arab armies and grabbing more territory than the UN plan invisioned.
Jordan annexes the West Bank and Jerusalem's Old City, Egypt occupies the Gaza Strip.
An armistice signed in Jan 1949, ends the first Arab-Israeli War. Israel increases the size of its territory by 40%. These borders become known as "The Green Line"
Curiously, Israel still refuses to accept any identified boundaries, and, Israel was established as a state for "Jewish People", not as a state for its citizens.