The blog
My Right Word writes about the importance of the date March 4, 1915 which is when
a group of Jews decided to establish a Jewish regiment that would participate alongside the British troops during WWI. He even has a copy of the document they all signed.
The most notable contributions to the British during WWI may well have been through the NILI spy ring, which provided intelligence about the Turkish military as well as the conditions in the area.
In
The Palestinian Right to Israel
, historian Alex Grobman describes the contributions made by NILI: