The Amazing Mr. Beecham (1949)

Young Viscount Tony Pym manages to get an army leave on the pretence of running for the Conservatives in the next local election. His only aim in fact is to marry June, a rich American heiress, before she returns to America. Due to unexpected circumstances, he is driven to take part in the election campaign but loses the vote. Humiliated, Tony must win June back so why not stand again, as a Socialist this time?