Liz Truss has pledged action this week on energy bills and insisted the country will "ride out the storm" but failed to set out details in her first speech as Prime Minister.
Addressing the nation outside No10, the new Conservative leader claimed she will "get Britain working again" - despite her party governing the country for the last 12 years.
She promised to pursue three early priorities, including multi-billion pound tax cuts, tackling soaring energy bills and also putting the NHS on a "firm footing" amid a major backlog.
"I know that we have to tackle those challenges," she said from a podium in Downing Street.
"Of course it won't be easy but we can do it. We will transform Britain into an aspiration nation," she said. "I will take action this day and every day to make it happen."'
The new prime minister added: "I'm confident that together we can ride out the storm, we can rebuild our economy and we can become the modern brilliant Britain that I know we can be.
"This is our vital mission to ensure opportunity and prosperity for all people and future generations. I'm determined to deliver."
In the coming hours, Ms Truss is also expected to announce a raft of cabinet appointments, with her close ally Kwasi Kwarteng widely tipped for the role of chancellor.
The pair will now be under intense pressure to announce a major package of economic support in the coming days to alleviate the cost-of-living crisis and surging energy bills.
Addressing the crisis, she failed to give any details, but said on Tuesday: "I will deal hands on with the energy crisis - I will take action this week to deal with energy bills."
She also paid tribute to Boris Johnson, describing him as a "hugely consequential prime minister".
It comes after the new Tory leader became prime minister on Tuesday after an audience with the Queen at Balmoral, Scotland, following Mr Johnson's resignation.
In his own valedictory speech outside No 10 at 7.30am, the former prime minister urged Tory MPs who had brought about his downfall to unite around the new leader Ms Truss.
"I say to my fellow Conservatives, it's time for politics to be over, folks," Mr Johnson said.
"It's time for us to get behind Liz Truss and her team, and her programme, and deliver for the people of this country. Because that is what the people of this country want".
Over a month after announcing his decision to resign as prime minister, Mr Johnson again expressed bitterness about how his departure came about - despite repeated scandals.
He said: "The batton will be handed over in what has unexpectedly turned out to be a relay race. They changed the rules halfway through, but never mind that now".
This breaking news story is being updated
