She faces an enormous task amid increasing pressure to curb soaring prices, ease labour unrest and fix a health care system burdened by long waiting lists and staff shortages.

Truss took office on Tuesday afternoon (Tuesday night AEST) at Balmoral Castle in Scotland, when the Queen formally asked her to form a new government in a carefully choreographed ceremony dictated by centuries of tradition.

It was the first time in the Queen’s 70-year reign that the handover of power took place at Balmoral, rather than at Buckingham Palace in London.

The ceremony was moved to Scotland to provide certainty about the schedule because the 96-year-old had experienced problems getting around that have forced palace officials to make decisions about her travel on a day-to-day basis.

At the top of Truss’s inbox is the energy crisis triggered by Russia’s invasion of Ukraine, which threatens to push energy bills to unaffordable levels, shuttering businesses and leaving the nation’s poorest people shivering in icy homes this winter.

She refused to spell out her energy strategy during the two-month campaign to succeed Johnson and now plans to cap energy bills at a cost to taxpayers of as much as £100 billion ($170.9 billion), British news media reported on Tuesday. She is expected to unveil her plan on Thursday.

“She’s making promises for that, as she says she’s going to ‘deliver, deliver, deliver’,” Rebecca Macdougal, 55, who works in law enforcement, said outside the Houses of Parliament.

“But we will see in, hopefully, the next few weeks there’ll be some announcements which will help the normal working person.”

As party leader, Truss automatically became prime minister without the need for a general election because the Conservatives still have a majority in the House of Commons.

But as a prime minister selected by less than 0.5 per cent of British adults, she is under pressure to show quick results.

Ed Davey, leader of the Liberal Democrats, on Tuesday called for an early election in October.

“I’ve listened to Liz Truss during the Tory leadership (campaign) and I was looking for a plan to help people with their skyrocketing energy bills, with the NHS crisis and so on, and I heard no plan at all,” he told the BBC.

“Given people are really worried, given people are losing sleep over their energy bills, businesses aren’t investing because of the crisis, I think that’s really wrong.”

‘Like Cincinnatus, I am returning to my plow’

He urged his supporters to get behind his successor, who was his foreign secretary.

In his final address outside 10 Downing Street on Tuesday, Johnson was bombastic, unapologetically verbose, poetic and strange.

“This is it, folks,” he said.

“The torch will finally be passed to a new Conservative leader.

“Through that lacquered black door, a new prime minister will shortly go to meet a group of fantastic public servants.”

His final speech as prime minister had the feel of an election pitch rather than a swan song.

He pointed to the remarkable speed of Britain’s vaccine rollout.

“That is government for you. That’s this Conservative government,” he said.

Johnson energetically touted the country’s future energy independence, particularly singing the praises of offshore wind power and nuclear reactors.

In two consecutive sentences, he likened himself to a booster rocket launching a spaceship out of the atmosphere, and to an ancient Roman statesman.

“I will now be gently re-entering the atmosphere, and splashing down in some obscure and remote corner of the Pacific,” Johnson said.

“Like Cincinnatus, I am returning to my plow,” he said.

Many Downing Street commentators were quick to research the former dictator and discover he had, in fact, returned to Rome.

He thanked his family, including his dog Dylan and cat Larry, the chief mouser to the Cabinet Office.

“If Dylan and Larry can put aside their differences, then so can the Conservative party.”

Larry has served under three prime ministers.