The TUC is stepping up attempts to make sure employment rights are not affected by the EU referendum result, amid fears workers are being "shafted".
Workers are still paying the price of the financial crisis, with wages £40 a week lower than before the crash, and they could face a fresh assault on pay and conditions as a result of Brexit, the union organisation said.
General secretary Frances O'Grady said she was determined to make sure unions have a voice in the negotiations taking place to prepare the UK for life outside the EU.
Speaking ahead of the TUC Congress, which opens in Brighton on Sunday, she revealed she plans to meet the Prime Minister in the coming weeks and will stress the importance of defending workers' rights.
She told the Press Association: "A lot of people in Britain feel they have been shafted. Working people should not pay the price of whatever will happen following the referendum.
"Six out of 10 union members voted to remain in the EU, but what is important now is bringing people together and making sure Brexit works for workers."
Ms O'Grady urged the Government to reassure EU workers their right to remain in this country will remain, and said it was not right to use people as "bargaining chips".
On prospects for the economy as Britain leaves the UK, she said: "There could be a rocky road ahead and it would be foolish to be complacent, which is why the Government should press ahead with airport expansion, HS2 and a programme of housebuilding, including council houses, which was needed well before the referendum."
On meeting Theresa May, the TUC leader said: "I am interested in what Theresa May said about social justice, Westminster being out of touch, making workers' lives better, as well as the promise of putting workers on company boards.
"This is recognition that something has gone badly wrong with corporate Britain. Sports Direct is in the spotlight now, but it is not the only place where there is outrage at working practices."
Some firms were being run by "glorified gangmasters", she added.