Households are facing the "grim reality" of Sir Keir Starmer’s warning that things in Britain "will get worse before they get better", according to the SNP.

The party's MP Kirsty Blackman hit out ahead of the first major speech by the Prime Minister since Labour's general victory when he is expected to argue that the change he promised in the campaign will take time saying the Conservatives left both an economic and societal “black hole” after their time in office.

During his address on Tuesday he is expected to both reflect on the action his government has already taken and pile more blame on the Conservatives for leaving a challenging inheritance.

“We have inherited not just an economic black hole but a societal black hole," he is expected to say.

“And that is why we have to take action and do things differently. Part of that is being honest with people – about the choices we face. And how tough this will be.

“Frankly – things will get worse before we get better.”

Ms Blackman said: “Labour spent their entire election campaign not being straight with voters about their financial plans and now Keir Starmer is being forced to admit the grim reality of what his Labour government means for households across the country.

“After 14 years of Westminster austerity hammering households, Labour have shamefully just picked up where the Tories left off and it is ordinary households who are being forced to pay the price - people want and deserve better.

“Against a backdrop of Westminster cuts putting serious financial pressure on the Scottish Government, the SNP will continue to do everything it can to protect our public services and people across Scotland."

Speaking on Sunday, Chancellor of the Duchy of Lancaster Pat McFadden told broadcasters the speech would represent a change from the rhetoric of the previous government.

He told LBC: “I think it’s a refreshing departure not to engage in some of the snake oil that has been sold to people in recent years and actually have a Prime Minister who says, look, we know it’s a tough situation. You know it’s tough. That’s why you voted for change.

“Change will come, but we’ve got to work through some of these challenges first.”

As well as highlighting problems in the public sector and blaming “cracks in our society” for making it harder to deal with the recent riots, Sir Keir will continue to criticise the Conservatives’ management of the public finances.

Rachel Reeves, the Chancellor, began that theme in her statement before the summer recess accusing the Tories of leaving a £22 billion black hole in this year’s budget.

Sir Keir is expected to develop that line of attack further on Tuesday, saying things are “worse than we ever imagined”.

But he will also reiterate his promise that change is coming, and argue that his Government has already achieved “more in seven weeks than the last government did in seven years”.

On Sunday, Mr McFadden added: “We have got a difficult economic inheritance, there is no point in running away from that, and we have a number of challenges. But we have already started work."

The Conservatives have rejected Sir Keir’s characterisation of their time in office, saying Labour is “squandering money” while “fabricating a financial black hole in an attempt to com the public into accepting tax rises”.

Tuesday’s speech comes a week ahead of Parliament’s return after a shortened summer recess and around two months before the Chancellor is due to deliver her first budget on October 30.

Questions remain over whether Labour will raise some taxes to cover the £22 billion funding gap it identified in the budget announced by Conservative Jeremy Hunt in the spring.

Mr McFadden reiterated his party’s commitment not to raise income tax south of the border, national insurance or VAT, and said the UK Government was not considering a 1% wealth tax proposed by the trade union Unite.

The Chancellor is also under pressure over her decision to means test winter fuel payments, restricting them to only the poorest pensioners in a bid to save £1.4 billion this year.

Charities, opposition parties and some Labour backbenchers have urged her to rethink the decision, saying some of those not eligible for pension credit could face a choice between paying for food and fuel in light of a 10% rise in the energy price cap this winter.

Mr McFadden told LBC he understood why people were “unhappy” about the decision, but said the Chancellor had an “overriding responsibility” to “ensure the public finances are on an even keel”.

First Minister John Swinney has said the means testing the winter fuel payment by the UK Government, meant a new successor benefit for pensioners in Scotland, which is devolved, would also be limited to those on the lowest incomes.