British households are being squeezed in the wake of the Brexit vote, a new study reveals.
Research by the TUC showed wages have fallen, economic growth has weakened and the UK's reliance on the European Union for trade has increased since the referendum to leave the EU.
The organisation called for the government to take action to strengthen the "spluttering" economy in preparation for Brexit.
In light of its findings, it urged Theresa May to invest in infrastructure and guaranteeing workers' rights to ensure the UK could hold its own as a major trading partner.
The report, published ahead of the opening day of the TUC Congress in Brighton, said growth had slowed in 11 industries in the year to June.
Only three employment sectors had seen real wage rises.
TUC general secretary Frances O'Grady said: "Our test for a successful Brexit is whether working people are better off. Throughout Brexit, the Government must protect jobs, and deliver stronger growth that reaches workers' pockets through higher pay.
"But with just 18 months to go before we leave, the economy is growing weaker, and Britain is simply not investing enough in the infrastructure we need to compete with the world's strongest economies.
A Government spokesman said: "As we leave the European Union, we will ensure that workers' rights are fully protected and maintained and we will build on our economic success by establishing a deep and special partnership with the EU while embracing the wider world as an independent, open, trading nation."
Shadow chancellor John McDonnell said: "The Tories are rushing into a cliff-edge Brexit with the economy sputtering.
"Only Labour can deliver the investment and industrial strategy we need to deliver good, secure jobs across the whole country, and we welcome the TUC's call for an immediate increase in infrastructure investment."