Struggling families desperate for help with soaring energy bills and the cost-of-living crisis will have to wait up to another week to find out what support they will get if Liz Truss wins the Tory leadership.
The No10 race victor will be unveiled at lunchtime tomorrow and become Prime Minister on Tuesday.
Foreign Secretary Ms Truss is the overwhelming favourite to triumph but has repeatedly refused to outline how she would help households.
Today she claimed: "I'm not being coy.
“What I've been very clear about is that I would act immediately, within a week. I understand what people are facing on energy bills."
Boris Johnson will fly to Scotland on Tuesday to formally resign to the Queen at Balmoral.
If she wins the Downing Street battle, Ms Truss will follow him 520 miles north where the monarch will invite her to form a Government.
The new PM faces a dire economic situation, with experts predicting a recession, inflation rampaging at 10.1 per cent, mortgage rates climbing and the energy price cap rocketing from £1,971 to £3,549 on October 1.
But with just hours until her anticipated arrival in No10, Ms Truss indicated her “precise plans” for tackling the misery may have to be overhauled.
“Before you have been elected as Prime Minister, you don't have all the wherewithal to get the things done,” she told BBC1's Sunday with Laura Kuenssberg.
“This is why it will take a week to sort out the precise plans and make sure we are able to announce them.
“That is why I cannot go into details at this stage; it would be wrong.
“But what I want to be very clear about with the public is I understand that this is a huge problem.”
Ms Truss’s bitter No10 rival - former Chancellor Rishi Sunak - warned the UK faces “a genuine emergency” on dual fuel bills.
But he is braced for defeat when the leadership contest result is announced at lunchtime. He is set to return to the backbenches.
Labour blasted the pair for failing to outline how they would help hard-up households worried about the economic storm.
Shadow Attorney General Emily Thornberry fumed: “We need to have real action and I am disappointed that we have yet to hear a proper plan coming from either of these leadership candidates.”
She feared more than half of families will plunge into fuel-poverty, where they spend 10% of their net income on gas and electricity.
Condemning Ms Truss for not revealing her plan, Ms Thornberry added: "We're going to have the majority of the country in fuel poverty unless something is done.
“What she says is, 'Oh well, I can't possibly tell you, I'll tell you in a week'. Why not?"
Campaigners criticised her for forcing anxious households to wait to hear what support will be coming.
Dennis Reed, director of the Silver Voices older people’s group, said he was “pretty appalled”.
He told the Mirror: “It seems that beyond soundbites she hasn’t got much of a clue what to do.
“She has been very precise about income tax cuts and the national insurance increases but she has said virtually nothing about what she will do for the millions of people who will struggle over the winter, and I’m surprised about that.
“She knows who her Chancellor will be and you would have thought, given the extent of the crisis, that the two of them would have got their heads together and have an oven-ready plan available for the first day she takes office.
“If she needs a week it means that there’s a lot still to be done, that’s she’s not really thought about it.
“It’s unforgivable.”
The Lib Dems’ Cabinet Office spokeswoman Christine Jardine warned: “The British public cannot wait another week for Liz Truss’s plans.
Get all the latest news sent to your inbox. Sign up for the free Mirror newsletter
“People are worried sick about the winter ahead and we need urgent support from the Government now before we face an energy catastrophe.
“Liz Truss must act on the eye-watering energy price rise on day one before millions face entering fuel poverty.”
Citizens Advice’s head of policy Morgan Wild said: “We’re already helping two people every minute with crisis support, and those numbers continue to head in the wrong direction.
“On a daily basis our advisers are raising red flags about the situations people are facing - people who are terminally ill and unable to heat their homes, parents going days without food to feed their kids and people unable to afford the bus fare to get to a food or school uniform bank.
“We need government support that matches the scale of this crisis - that means a financial lifeline for those who need it and better protections when people can’t afford their bills.”
The Scottish National Party’s Fiona Hyslop said: “If Truss, as expected, replaces Johnson as Prime Minister, she must provide an appropriate, comprehensive and substantial package of measures to help both families and businesses weather this storm that the inept Tories helped create.”
Insiders claimed Ms Truss’ cost-of-living plan will “easily exceed” £100billion, most of which will be slapped on the national debt.
The No10 hopeful did not deny the figure when it was put to her by the BBC.
Ms Truss is expected to spend her first hours in No10 on Tuesday appointing senior ministers.
She is due to host her first Cabinet meeting on Wednesday morning before heading to Parliament for her first Prime Minister's Questions clash with Labour leader Keir Starmer.
Meanwhile, she insisted her plan to reverse the rise in national insurance was "fair" despite it directly benefiting higher earners.
She wants to U-turn on April's national insurance hike and next year's planned corporation tax increase from 19 per cent to 25 per cent.
“I am absolutely determined to sort out this issue as well within a month, present a full plan for how we are going to reduce taxes,” she said today.
But warned that reversing the national insurance rise would see the poorest stand to gain about £7 while the wealthiest people could gain nearly £2,000, she hit out: "It is fair.”
She added: "The people at the top of the income distribution pay more tax so inevitably when you cut taxes you tend to benefit people who are more likely to pay tax.”
