A Scottish local council has lost a long running equal pay battle with more than 250 female employees, leaving a "mammoth" task for its payroll department.
The women who all worked as classroom assistants and nursery nurses for Dumfries and Galloway Council could be in line for a share of £12m in back pay, after successfully proving in court that their ineligibility for a bonus amounted to discrimination.
The case went to the Supreme Court after an earlier Court of Session hearing ruled that the 251 employees could not compare jobs at a similar pay grade but at a separate location.
A number of Scottish councils were in support of Dumfries and Galloway's legal stance, and will also be forced to review their payrolls.
Jason Jones, head of employee services at Warrington Borough Council, who has been involved in supporting the roll out of equal pay terms and conditions across a workplace, said: "Pay equalisation is a mammoth task for payrollers, especially historical cases or where payroll software does not retro calculate beyond financial years.
"The real difficulty at the payroll end is actually calculating the correct amount due to the employee. In every case I have been involved in it has meant that from the effective date of the award, each and every change that has occurred has had to be recalculated and adjusted manually.
"This is not so difficult where someone works in a static full time position, but life in payroll is never that simple. To be calculated correctly, everything needs to be taken into account - even the correct tax, NIC and pension deductions for the appropriate year."
The women were supported in their legal battle by their trade union Unison.
Dave Prentis, Unison general secretary, said: "I am delighted that the Supreme Court has ruled in favour of our women members. It is a shame, though, that they have had to go through this process and endue a seven-year wait, just to get equal pay. Dumfries and Galloway Council should take immediate steps to correct their pay and I urge other councils to follow suit."
Following the court ruling, a spokesman at Dumfries and Galloway Council said: "This judgement has implications for many local authorities and other public bodies. Our Council will now consider its position in response to the Supreme Court judgement."