Boris Johnson formally takes charge as Britain's new PM

Boris Johnson officially became Britain's new Prime Minister on Wednesday, a day after his landslide victory in the Conservative Party leadership contest.

The 55-year-old former foreign secretary and London Mayor met Queen Elizabeth II, who asked him to form a new administration, Buckingham Palace said in a statement.

A picture released by the palace showed Johnson shaking hands with the 93-year-old monarch and bowing.

Johnson will now lay out his vision as Prime Minister in his first speech on the steps of Downing Street.

"We are going to energise the country. We are going to get Brexit done on October 31 and take advantage of all the opportunities it will bring with a new spirit of can do," said Johnson, soon after being confirmed as the new Conservative Party leader and Prime Minister-elect on Tuesday.

"The mantra is deliver Brexit, unite the country and defeat [Labour leader] Jeremy Corbyn," he added.

Theresa May, who was forced to resign amid a mounting rebellion from within her party over her Brexit strategy that failed to clear the Parliament votes threshold three times, earlier in the day formally tendered her resignation to the Queen.