Voting is set to close later on Monday in the Conservative leadership contest.
Party members have until 5 pm UK time to vote for either Jeremy Hunt or Boris Johnson as their next Tory leader.
Johnson, who is the former mayor of London and the ex-Foreign Secretary, is widely considered to be the favourite in the race.
The UK's next prime minister will be announced on Tuesday, and he will take office a day later, succeeding Theresa May.

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