Britain’s Conservative Party has started the first round of voting to choose the next prime minister of the United Kingdom. The 330 MPs of the party have till 6 pm (British Summer Time) to cast their votes. Once the results an hour later, the candidate with the least number of votes will be eliminated from the race, BBC reported.

David Cameron, who had campaigned for Britain to remain in the European Union, resigned as the UK prime minister after the Brexit vote. As much as 51.9% of Britain voted for UK to no longer be part of the EU, in a referendum on June 23. The result has seen protests from those who voted against Brexit.

While Home Secretary Theresa May has the support of the most number of MPs, Boris Johnson announced his support for Energy Minister Andrea Leadsom on Monday. Other candidates in the fray are Michael Gove, Stephen Crabb and Liam Fox.

Senior Conservative MP Charles Walker is supervising the vote, which is being held in the Parliament’s Committee Corridor. To bring the number of candidates down to two, the next few rounds in the selection process will be held on Thursday and the following Tuesday. Members of the party will choose from two candidates with the highest backing from MPs. The winner will be declared on September 9.