Glasgow City Council workers march for equal pay during a 48-hour strike that began Tuesday.
CNN  — 

Thousands of public-sector workers in Scotland’s largest city walked off their jobs Tuesday, marking the start of a 48-hour strike over a long-running pay dispute.

An estimated 8,000 people – mostly women from Glasgow’s schools, nurseries, care homes and catering and cleaning industries – are expected to join the industrial action, believed to be the largest of its kind since the UK passed the 1970 Equal Pay Act prohibiting workplace wage discrimination on the basis of sex.

The striking workers say the local government, Glasgow City Council, has been too slow to act on thousands of legal claims lodged on equal pay dating back more than a decade.

In 2006, the local authority implemented a pay and benefits program aimed to close the pay gap.

But that plan had the opposite effect, with workers in female-dominated roles receiving up to £3 ($3.90) an hour less than workers in roles dominated by male workers, according to campaigners.

Last year, Scotland’s highest civil court ruled that the 2006 program had discriminated against women workers and that thousands of them had been excluded from bonuses. In January, the local authority said it planned to negotiate a settlement for some 12,000 claims lodged by those workers.

But 10 months later, union leaders say that the city authority has “agreed nothing, offered nothing,” and that the time had come to take action in hopes of putting “an end to this long-standing injustice.”

Mandy McDowall, a regional organizer for the Unison trade union, said: “It is a modern-day scandal that nearly 50 years on from the equal pay act being introduced we find ourselves standing alongside thousands of women who are being discriminated against by one of the UK’s largest councils.”

“These women are the lifeblood of Glasgow, they carry out vital roles across the city – cleaning, caring, educating and looking after some of the most vulnerable people in our society. They are the cogs that keep our city turning yet their roles remain chronically undervalued. Strike action isn’t a decision these women have taken lightly but after months of empty promises they have been left with no choice.”

Action 4 Equality Scotland, a legal action campaign group, estimates that the claims could cost the local government between £500 million (approximately $649 million) and £1 billion. Glasgow City Council told CNN that the total cost of the equal pay claims “is still being calculated.”

“We understand why many of our workforce are angry about equal pay, but there is nothing that this strike can achieve that we are not already doing,” a Glasgow City Council spokesperson said in a statement Tuesday.

The spokesperson said that the council is “absolutely committed to delivering equal pay and reaching a negotiated settlement” and that the action was negatively affecting the city’s elderly and most vulnerable.