The number of workers taking claims of unfair dismissal or discrimination to employment tribunals has slumped since charges came into force, a new study has revealed.
Unfair dismissal claims have fallen by 73% and there have been huge reductions in discrimination cases on grounds of sex (71%), race (58%) and disability (54%), since charges of up to £1,200 were introduced, said the TUC.
The number of workers taking claims to a tribunal averaged 16,000 a month in 2012/13, but that figure collapsed to 7,000 in the past year, said the union organisation.
The TUC warned the figures showed that discrimination and unfair sackings were being allowed to flourish "unchecked".
The Government is being urged to abolish the fees in this month's Autumn Statement.
TUC general secretary Frances O'Grady said: "These figures show a huge drop in workers seeking justice when they've been unfairly treated. Now bosses know they can get away with it, discrimination at work can flourish unchecked and people can be sacked without good reason.
"The evidence is there for all to see. These fees - of up to £1,200, even if you're on the minimum wage - are pricing out thousands each month from pursuing cases.
"Theresa May has repeatedly said she wants to govern for ordinary working people. Here is a perfect opportunity.
"She could reverse employment tribunal fees, and make sure workers can challenge bad employers in court."