This question has a big incorrect assumption, namely that Israel was given by Western powers to the Jews. This is not really accurate. The Jewish movement for a Jewish state preceded any country approving of it. Zionism got an initial rubber stamp from the British after WW1, but this was a plan, not anyone giving anyone anything. In the meantime the British controlled Palestine as a quasi-colony, promising that the land would be part of both a Jewish and an Arab state.

In between Zionism as a political ideology became increasingly popular among Jews. After WW2, there was a large population of Jewish refugees in Europe that had nowhere to go. The British, then in charge of Palestine, refused to allow them entry (they had developed immigration limits to try and lessen the violence that was beginning to spiral out of control). This refusal made the British position very unpopular, and other countries came to support the Jewish position.

Eventually British rule was completely untenable. The UN voted that a Jewish state should be established, and the British evacuated their troops and left the Jews, Palestinians, and Arab countries to sort it out on their own.

So in short, no one "gave" Israel to the Jews. A number of countries were in favor of Israel's establishment for a wide variety of reasons, including the successful agitation of refugees in Europe. Israel declared independence after they felt the UN vote a year earlier had authorized them to do so. The British "handing them the keys", so to speak (which they did because they declared independence, the British were leaving, and the UN said a Jewish state ought to exist there), only occurred sporadically and had very little practical meaning.