Conservative Party members in the UK have been warned that they can only vote once in the upcoming leadership election.
It's after the party admitted some members could be sent more than one ballot paper.
Party chair Brandon Lewis said people registered at more than one address or who have recently changed their names could be affected.
The BBC this morning reported that more than a thousand people may have been issued with multiple ballot papers.
Members are being asked to choose between the former Foreign Secretary Boris Johnson and the man who took over from him, Jeremy Hunt, to take the leadership of the party after Theresa May steps down.
With the vote, the 160,000 members are also effectively choosing who will become the next UK Prime Minister.
Mr Johnson looks on course for a landslide victory – with the latest YouGov/Times Poll handing him 76% of the vote.
Mr Hunt has urged the members not to cast their vote until after two head-to-head television debates, scheduled for next week.
Voting closes on July 22nd with the winner due to be announced the following day.