The Government is to take immediate steps to stop charging employment tribunal fees and refund those who have paid following a "landmark" Supreme Court ruling.
The Ministry of Justice said it accepted a Supreme Court judgment in favour of public sector union Unison which has fought a four-year battle against controversial fees of up to £1,200 for taking a case to a tribunal.
The Supreme Court ruled unanimously in favour of the union, which had argued that the fees discriminated against women and other groups of workers.
The court ruled that the Government was acting unlawfully and unconstitutionally when it introduced the fees four years ago.
Unison said the Government will have to refund more than £27 million to the thousands of people charged for taking claims to tribunal since July 2013, when fees were introduced by Chris Grayling, the then lord chancellor.
General secretary Dave Prentis said: "The Government is not above the law, but when ministers introduced fees they were disregarding laws many centuries old, and showing little concern for employees seeking justice following illegal treatment at work.
"The Government has been acting unlawfully, and has been proved wrong - not just on simple economics, but on constitutional law and basic fairness too.
"It's a major victory for employees everywhere. Unison took the case on behalf of anyone who's ever been wronged at work, or who might be in future. Unscrupulous employers no longer have the upper hand.
"These unfair fees have let law-breaking bosses off the hook these past four years, and left badly treated staff with no choice but to put up or shut up.
"We'll never know how many people missed out because they couldn't afford the expense of fees, but at last this tax on justice has been lifted."
Justice Minister Dominic Raab said: "In setting employment tribunal fees, the Government has to consider access to justice, the costs of litigation, and how we fund the tribunals.
"The Supreme Court recognised the important role fees can play, but ruled that we have not struck the right balance in this case. We will take immediate steps to stop charging fees in employment tribunals and put in place arrangements to refund those who have paid.
"We will also further consider the detail of the judgment."
David Isaac, chairman of the Equality and Human Rights Commission, said: "Thousands may have been denied of this right and priced out of getting justice.
"The judgment of the Supreme Court is a damning verdict on the current regime."
A review of the impact of the fees earlier this year showed there had been a 70% drop in the number of cases since they were introduced in 2013.
TUC general secretary Frances O'Grady said: "This is a massive win for working people.
" Too many low-paid workers couldn't afford to uphold their rights at work, even when they've faced harassment or have been sacked unfairly.
"Tribunal fees have been a bonanza for bad bosses, giving them free rein to mistreat staff.
"Any fees paid so far should be refunded as soon as possible."