Scores of women who worked at a local authority have won an equal pay fight in the UK's highest court which lawyers say will have "serious ramifications" for employers.
The Supreme Court had "effectively" extended the time workers have to bring equal pay compensation claims from six months to six years, said solicitors.
Experts said the ruling could trigger thousands of claims and have a "significant impact" in the City.
About 170 former Birmingham City Council employees - including women who worked as cooks, cleaners and care assistants - who left their jobs between 2004 and 2008 want compensation.
They say the council made payments and provided benefits to men doing the same level of work - but not to them. Their lawyers claim that the council breached equal pay law.
Birmingham council tried to block claims - arguing that should be taken to employment tribunals, which have a six-month time limit.
But former employees persuaded judges that they could bring claims in civil courts, where there is a six-year limit.
The women had earlier won fights on the issue in the High Court and the Court of Appeal and the Supreme Court dismissed Birmingham council's challenge to the Court of Appeal decision on Wednesday.
A law firm which represented the women said the decision was "historic" and had "huge implications". "The judgment effectively extends the time limit for equal pay claims from six months to six years, the biggest change to Equal Pay legislation since it was introduced in 1970, with huge implications for thousands of workers," said a spokesman for law firm Leigh Day & Co.
Lisa Mayhew, an employment specialist at law firm Berwin Leighton Paisner, said: "Although this case originated in the public sector today's decision it may well have a significant impact on the City, where female employees may now be more willing to bide their time and bring equal pay claims to the High Court. The Supreme Court judges decided that the High Court does have jurisdiction to hear an equal pay claim when the time limit of six months to bring an equal pay claim in the Employment Tribunal has already expired. This means that equal pay claims could be viewed as more lucrative and worthwhile pursuing by staff - a worrying prospect for employers."