The Balfour Agreement in 1917 is the most relevant area to research. UK foreign secretary Lord Balfour gave the Balfour Agreement to Lord Rothschild as head of the World Zionist Organisation. The Balfour Agreement is a promise from the UK government to help establish a Jewish state in what was then British mandated Palestine. That is the who and the what. The why is a deeper question. Why bankers represented World Zionism is already waving red flags. A year from the end of WW1, what was the quid pro quo that the UK government had with bankers?
The above facts are matters of record and not contested. Lord Balfour handed the agreement to Lord Rothschild as representative of the Zionists.