It's debated whether a united kingdom of Israel existed. I guess it depends on how literally you want to take the bible. I've seen it argued (from Jewish people, not just anti-Semites, although they love this) that Judaism forbids them from having a nation state until the coming of the Messiah. Which of course is never going to happen, right?
That's where Zionism comes from, and was supported by Britain early on, supporting their migration into the territory, and eventually United Nations setting up borders.
Many countries, including Canada and the US (minus 4 years under Trump), are in favor of setting up a Palestinian state under the 1967 borders (so give them back the West Bank and East Jerusalem along with Gaza).
You can see how the borders changed from post WW1 migration, to the original UN plan, to 1967.
