Ex-Foreign Minister and former London Mayor Boris Johnson is expected to be elected head of the British Conservative Party, the ruling committee of the party announced on Tuesday, CNN reported. 

Johnson will become the country's prime minister on Wednesday, after replacing current PM Theresa May.

The finalists of the race were determined after a series of ballots by the faction of the ruling Conservative Party in the House of Commons, but the final decision was left to the ordinary members of the Tory party who voted by mail.

The official transfer of power from the current prime minister to a new one will take place on Wednesday, after the last session for May to answer questions from MPs in parliament. Queen Elizabeth II will accept the resignation of May and ask the new prime minister to form a government. Appointments to key positions are expected to be announced on Wednesday evening.