The Government has been accused of a "criminal" lack of preparation for Brexit amid increasing calls for workers' rights to be protected as the UK leaves the EU.
TUC general secretary Frances O'Grady said the clock was ticking towards a "kamikaze" Brexit, with no proper assessment yet carried out about the impact on industries.
Speaking on the opening day of the TUC Congress in Brighton, she said the government had no action plan to protect jobs and employment rights.
Ms O'Grady told a news conference: "Over the last year the Government's criminal lack of preparation for March 2019 has become clear.
"The Prime Minister needs to break free from the hardliners in her party who want a cliff edge Brexit."
Ms O'Grady also warned against the danger of a "sweatshop" Brexit, with UK workers falling behind the rights that other Europeans enjoy.
She said: "It's galling to see a Government that promised to protect workers' rights put forward a Bill on EU withdrawal that's full of loopholes on workers' rights.
"It will give ministers the power to water them down and let any future government attack them."
The TUC is calling for the UK to stay in the single market and customs unions during a transition period.
A statement issued by the TUC general council before the start of the conference said the UK needed a tariff-free, frictionless trade in goods and services with the rest of Europe.
The statement said the TUC was "alarmed " that industrial investment has declined sharply this year.
The trade deficit has widened, economic growth has slowed and wages have "stagnated", it added.