New Prime Minister Keir Starmer has said Britain needed to rediscover its identity and undergo a wider reset, in his first words outside his new office at 10 Downing Street, promising to fight to restore trust in politics and serve all voters.

Greeted in Downing Street by a large crowd of cheering aides and supporters after formally accepting the King's invitation to become prime minister, Starmer's first address made the case for moderate politics to repair voters' broken trust.

"It is surely clear to everyone that our country needs a bigger reset, a rediscovery of who we are, because no matter how fierce the storms of history, one of the greatest strengths of this nation has always been our ability to navigate a way to calmer waters," he said.

"This depends upon politicians, particularly those who stand for stability and moderation, as I do."

He added: "My government will fight every day until you believe again. From now on, you have a government unburdened by doctrine, guided only by the determination to serve your interest. To defy those quietly those who have written our country off."

"You have given us a clear mandate, And we will use it to deliver change."

Sunak quits

Rishi Sunak on Friday resigned as prime minister and Conservative Party leader after losing heavily to Starmer's Labour Party, leaving with an apology, a tribute to Britain, and a call to protect "kindness, decency and tolerance".

His defeat ended 14 years of Conservative government — a period marked by division, political instability and, more recently, economic pain. He hands control of the world's sixth-largest economy to centre-left Labour Party leader Keir Starmer.

"I have given this job my all, but you have sent a clear signal that the government of the United Kingdom must change, and yours is the only judgement that matters," Sunak said in a speech outside the prime minister's office in Downing Street.

"I have heard your anger, your disappointment and I take responsibility for this loss."

Sunak said whatever their disagreements, he respected Starmer as a "decent public-spirited man".

"He and his family deserve the very best of our understanding as they make the huge transition to their new lives behind this door," he said.

Sunak's tone marked a stark contrast to his approach to the final weeks of the campaign when, increasingly desperate as the opinion polls refused to budge, he tore into Starmer, warning the Labour leader would hike taxes, hammer the economy and threaten its security.