Baroness Ros Altmann, a member of the British House of Lords and a minister in the Conservative government, was recently exposed as someone who had joined the Labour Party last year. All dues-paying members of the Labour Party received a postal ballot to vote on who the Labour Party leader should be. In Britain, party leaders become Prime Minister if that party wins the election.
The Labour Party combed through its membership list last month and expelled persons who are active members of other parties, but the process missed Baroness Altmann. See this story. She received a ballot, but the story does not say if she used that ballot. The votes are being counted now and the winner’s identity will be announced this week.