Britain's head of state, King Charles III, on Friday officially appointed Labour leader Keir Starmer as prime minister at Buckingham Palace.

A photograph released by the palace showed the monarch shaking hands with Starmer, whose party achieved a landslide victory in the general election, bringing an end to 14 years of Conservative rule.

The King had earlier accepted the resignation of Conservative leader Rishi Sunak as prime minister.

"The King received in Audience The Right Honourable Sir Keir Starmer MP today and requested him to form a new Administration," confirmed a statement by the Buckingham Palace.

"Sir Keir accepted His Majesty's offer and kissed hands upon his appointment as Prime Minister and First Lord of the Treasury," it added.

Starmer vows Labour will 'rebuild Britain'

Later, Starmer arrived at Downing Street for the first time as UK prime minister, vowing to take immediate action to restore the nation's fortunes.

"The work of change begins immediately," Starmer told reporters outside Downing Street after accepting King Charles III's invitation to form a government.

"But have no doubt, we will rebuild Britain," he stressed.

Starmer, 61, faces a formidable to-do list, acknowledging that Britons had grown weary of deteriorating public services, rising prices, and unfulfilled political promises.

He promised that his government would prioritize "country first, party second" and restore "respect for politics" after a series of scandals under the Tories that damaged public trust.

However, he sought to manage expectations of rapid change, saying, "Changing a country is not like flicking a switch."