The Prime Minister’s commitment to have workers on company boards could be law within a year if Theresa May presses ahead quickly with the move, according to the TUC.
The union organisation said a new law should apply to all firms with workforces of more than 250, and could be phased in gradually, starting with larger businesses.
In a report, the TUC calls for a third of company board members to be worker representatives, saying they should be directly elected by their colleagues, as happens in 12 other EU member states.
The TUC argued that the current approach of relying on shareholders to hold companies to account has not delivered economic success or social justice.
General secretary Frances O’Grady said: “The TUC stands ready to work with Theresa May to make workers on boards a reality. If the political will is there, this policy can be on the statute books within a year.
“The European experience shows that improving worker representation is not something for UK firms to fear. It helps improve company performance.
“These are common sense plans. Those on the shop floor have a clear interest in the long-term success of their companies and deserve a bigger say.
“Seats for the workforce on company boards would do much to improve the reputation of corporate Britain. It is essential the Prime Minister holds her nerve and resists any calls to water down the proposals.”
A Business Department spokesman said: “As the Prime Minister set out at the G20 last month, to restore greater fairness, we will bring forward a consultation this autumn on measures to tackle corporate irresponsibility, cracking down on excessive corporate pay and poor corporate governance, and giving employees and customers representation on company boards.”