A spectacular breakthrough in the battle for equal pay for women is expected to cost the National Health Service tens of billions of pounds.

A spectacular breakthrough in the battle for equal pay for women is expected to cost the National Health Service tens of billions of pounds.

A test case taken by the public service union Unison is to deliver payments to workers estimated to be worth between £35,000 and £250,000 each.

After an eight-year legal battle, North Cumbria Acute NHS Trust will be forced to pay up to £300m in compensation to its female employees for 14 years of discrimination.

The large sums involvedcall into question the ability of the trust to cope with the award, which is expected to be made throughout the health service.

Under legislation on equal pay for work of equal value, a panel of experts has agreed that the work of a range of employees - from nurses to catering staff - should carry the same wages as specific jobs mostly held by men. That ruling is expected to go before an employment tribunal next Monday, which will calculate the exact compensation due.

The NHS pointed out yesterday that payments had not yet been fixed, but a Unison spokeswoman said the trust had little room to manoeuvre. She said there was discussion over which point on a particular pay scale was appropriate for calculating compensation.

The equal pay claims at the Cumbrian trust were lodged in August 1997 for 14 jobs using five male "comparators''. The women ranged from nurses to catering assistants, domestics, clerical officers, sewing machine assistants, porters and telephonists. They compared their pay with that of joiners, building labourers, wall-washers, craftsmen, supervisors and maintenance assistants.

Under the law women can claim up to six years' back pay. Some of the claimants at the Cumbrian trust will receive up to 14 years of compensation including interest at between 50 and 60 per cent, the union says.

Pay, hours of work, pensions, weekend working rates and sick pay were all included in the comparisons to determine that women were treated unfairly by the old system.

Dave Prentis, general secretary of Unison, said: "It's been a long, hard struggle, but this is a fantastic result for the members involved. This demonstrates what we have always argued, that there has been historic widespread pay discrimination in the health service against women. It's dreadful, though, that it has taken so long to get justice for these hard-working women who hold the health service together.''

Mr Prentis said that a newly negotiated pay system, Agenda For Change, would remedy the discrimination. "This decision means that we will now press our claim for back pay for other health service staff who may have suffered from an unfair pay system.'' He said the union intended to negotiate back pay with NHS management rather than return to litigation.

Christine Wharrier, a Unison convener who has worked at West Cumbria Hospital for 28 years as a healthcare assistant, said that it was a "great victory'' for women throughout the health service.

"Discrimination runs deep in the NHS, especially for part-timers, who are mainly women workers. This win will be a boon for ancillary staff because they are on really low pay.''

Linda Weightman, a nurse at Cumberland Infirmary, said: "It's taken a long time, but it's been worth it. Over the years people have kept asking me, 'Do you think we will win?' and I kept saying how can we not win, because we are right?''