At the 1906 general election Branch successfully contested the parliamentary constituency of Enfield, one of many Liberals who unseated sitting Conservative MPs.[2] He was defeated at the next election in January 1910, following a campaign where his Conservative opponents alleged that he was a Polish Jew and was using a false name. They also falsely claimed that he had discharged his British employees in favour of foreign workers.[9][10] He attempted to regain the seat at the next election in December of the same year, but failed to be elected.[11]