The Prime Minister has been accused of "abandoning" promises she made to help working families after new research revealed that households have been pushed £1,250 into the red since her arrival in Downing Street.
The TUC criticised Theresa May's promise to help so-called just-about-managing families, saying they had been pushed closer to a financial "cliff edge" in recent years.
Families are now being forced to borrow to maintain a basic standard of living, with debt levels rising "extremely quickly" among the poorest, said the union organisation.
Its analysis of official data showed that families' outgoings have outstripped their incomes in every quarter since Mrs May took office in 2016.
The TUC said disposable incomes have fallen at an annual rate of 0.4% over the past two years, driven by falling wages and insecure work.
Pay and work will dominate next week's TUC Congress in Manchester, when there will be calls for a crackdown on insecure work, an end to "unfair" pay for agency employees and banning of zero-hours contracts.
TUC general secretary Frances O'Grady (pictured) said: "Theresa May has abandoned the promises she made when she moved into Downing Street.
"Two years on, working families can't make ends meet without being forced into the red, and the May Government has done nothing to get wages rising or to crack down on the epidemic of insecure work.
"It's time for the Prime Minister to get serious about domestic issues. Families on the edge need more than empty words.
"For a start, she must do something to tackle insecure work."
Ms O'Grady told the Press Association that the Government was paying "no attention" to issues facing "real people" because of its obsession with Brexit and internal squabbles.
"It will be another seven years before pay returns to pre-crisis levels, but what is the Government doing about it?
"It is our job to try to get some focus back on what needs to happen to improve working lives."
Ms O'Grady said just-about-managing families were "just about drowning", adding: "We need to start talking about a fair economy."
Brexit will also be debated at the conference, with the TUC continuing to warn about the impact on workers' rights if the UK "crashes" out of the EU without an agreement.
Ms O'Grady said there was a growing appetite for a public vote on the final Brexit deal, adding: "My personal preference would be an early general election."
A Government spokesman said: "Since 2010 we've supported more people into work, introduced the National Living Wage worth £7.83 per hour, doubled free childcare and helped workers keep more of the money they earn at the end of every month by cutting taxes for 31 million people by an average of £1,000.
"Our balanced approach means we have done this whilst reducing the deficit, spending £20 billion more per year on the NHS and increasing pay for teachers, nurses and soldiers.
"We are spending £90 billion a year on working-age welfare, and we will be spending £28 billion more on welfare by 2022 than we do now."
Copyright (c) Press Association Ltd. 2018, All Rights Reserved. Picture (c) Andrew Matthews / PA Wire.