Former foreign secretary Truss beat rival Rishi Sunak to win the Conservative Party leadership race, with the result announced on Monday (September 5).
She said: “History will see him as a hugely consequential prime minister.”
Addressing voters, Ms Truss admitted: “We now face severe global headwinds caused by Russia’s appalling war in Ukraine and the aftermath of Covid.”
But she insisted the country “can become the modern brilliant Britain that I know we can be.
“We will transform Britain into an aspiration nation with high-paying jobs, safe streets and where everyone everywhere has the opportunities they deserve.”
And referencing Winston Churchill, she added: “I will take action this day, and action every day, to make it happen.”
On her first three priorities, she stressed her focus would be:
- The economy, with plans to increase jobs, cut taxes and boost investment;
- Tackling the energy crisis with action “this week” to address bills and supply;
- And ensuring people can get the GP appointments and NHS services they need.
Closing her remarks, before entering No10 with her husband Hugh O’Leary, Ms Truss said: “This is our vital mission to ensure opportunity and prosperity for all people and future generations.
“I am determined to deliver.”
Commenting on the speech, Labour deputy leader Angela Rayner said: “Liz Truss is not on the side of working people.
“While families are sick with worry about how they will pay their energy bills this winter, Liz Truss is giving handouts to companies.
“Labour has set out a fully funded plan to ensure no one pays a penny more on their energy bill this winter.
“Because Labour is on the side of working people, while the Tories are the party protecting oil and gas profits.”
And London mayor Sadiq Khan said: “I believe Liz Truss and I have a common desire to see London thrive.
“We may come from different political traditions, but I hope we are able to work together to improve the livelihood of all Londoners and help those in need through this difficult time.
“I want to work together with our new Prime Minister to help struggling families and businesses.
“I hope what unites us is a common desire to see our capital city thriving and our country succeeding.”
Labour leader Sir Keir Starmer said on Monday: “I hope Liz Truss can meet the challenges facing this country.
“But so far, she’s spent more time talking about cuts to corporation tax than the cost of living crisis.
“She must back Labour’s plan to freeze energy bills, paid for by a windfall tax on oil and gas companies.”
Ms Truss and Sir Keir are set to face each other at Prime Minister’s Questions today in the House of Commons in what will be her first appearance in Parliament as prime minister.