LONDON — Until Britain voted to leave the European Union, Philip Levine never thought deeply about his Jewish heritage.

But looking for a way to ensure that he could still work and live in Europe once Britain leaves the bloc, Mr. Levine, 35, who was born in Britain and lives in London, decided to do what some Jews, including his relatives, might consider unthinkable: apply for German citizenship.

He did so by employing a provision of German law that has been on the books since 1949 but that has been little used in recent years. With some exceptions, it allows anyone whom the Nazis stripped of their German citizenship “on political, racial or religious grounds” from Jan. 30, 1933, to May 8, 1945, and their descendants, to have their citizenship restored. (For those born before April 1, 1953, German citizenship can be derived through the father only.) Most of those who lost their citizenship during that period were Jews, though they also included other minorities and political opponents.

He is not alone in turning to the German law after Britain’s decision to end its membership in the European Union, also known as Brexit. Since the vote in June, the German Embassy in London said it had received at least 400 requests from Britons for information about German citizenship under a legal provision known as Article 116.