Liz Truss has officially been appointed as the United Kingdom’s new prime minister by Queen Elizabeth II.

On Tuesday, Buckingham Palace officially recognised Ms Truss as the country’s third female prime minister after Theresa May and Margaret Thatcher in a statement. 

“The Queen received in Audience The Right Honourable Elizabeth Truss MP today and requested her to form a new Administration,” the statement said. “Ms Truss accepted Her Majesty’s offer and kissed hands upon her appointment as Prime Minister and First Lord of the Treasury.”

Former prime minister Boris Johnson also visited Balmoral Castle on Tuesday to tender his resignation to the Queen.

In his last speech as the prime minister, Mr Johnson said his policies gave the country the economic strength to help people survive during the energy crisis. 

“I am like one of those booster rockets that has fulfilled its function,” Mr Johnson said.

On Monday, Ms Truss was announced the winner of the internal election held by the Conservative party members after Mr Johnson resigned in July and the hustings began to replace him.

She had served as Mr Johnson’s foreign secretary and won the election by 57 per cent, garnering 81,326 votes of Conservative Party members to become its leader. Former finance minister Rishi Sunak took 43 per cent with 60,399 votes.

Ms Truss is expected to make her first speech as Prime Minister outside 10 Downing Street at about 4:00 p.m. today.