Former Foreign Secretary and London Mayor Boris Johnson was on Tuesday elected as Conservative party leader, automatically making him the next UK Prime Minister.
He beat Jeremy Hunt comfortably, winning 92,153 votes to his rival's 46,656. He will replace Ms May on Wednesday, following her resignation in June this year.
Mr Johnson will be confirmed by the House of Commons before confirmation by Queen Elizabeth II as part of the constitutional requirement.
In his victory speech, Mr Johnson promised he would "deliver Brexit, unite the country and defeat Jeremy Corbyn".
Speaking at the Queen Elizabeth II centre in London, he said: "We are going to energise the country."We are going to get Brexit done on 31 October and take advantage of all the opportunities it will bring with a new spirit of can do.
"We are once again going to believe in ourselves, and like some slumbering giant we are going to rise and ping off the guy ropes of self doubt and negativity."
Foreign Secretary Mr Hunt said he was "very disappointed", but Mr Johnson would do "a great job". He said he had "total, unshakeable confidence in our country" and that was a valuable quality at such a challenging time.
Mr Hunt added: "It was always going to be uphill for us because I was someone who voted Remain and I think lots of party members felt that this was a moment when you just had to have someone who voted for Brexit in the referendum. "In retrospect, that was a hurdle we were never able to overcome."
Ms May visited Kenya last year and held talks with President Uhuru Kenyatta. She became the first PM to visit Nairobi since 1988. The outgoing PM termed Kenya as a strategic partner.
In 2017, Boris Johnson also visited Kenya where he had talks with President Uhuru Kenyatta at State House over the relationship between the two countries.
Incidentally, the change of guard is taking place at the time UK had pledged support in graft war. Outgoing High Commissioner Nick Hailey last week promised London's support in the graft purge.
Mr Johnson will be addressing the world about UK's internal and external policies with Brexit being among his major agendas. He becomes third Conservative leader in 5 years.