Legal experts today questioned whether a landmark European court ruling that allows employers to continue to reward staff based on length of service discriminates against younger workers.

Yesterday's ruling from the European Court of Justice, billed as the most important sex discrimination judgment for ten years, means that women who take time out to care for their children have no automatic right to the same rate of pay as colleagues who have not taken career breaks.

Bernadette Cadman, 44, a health inspector from Manchester, brought the case after she realised that she was being paid up to £9,000 less a year than male colleagues who were doing the same job as her.

Her union, Prospect, took some comfort from the ruling's view that workers have a right to challenge service-based pay systems in court if they could raise "serious doubts" about whether length of service enabled a worker to do their job better than a less experienced member of staff. Ms Cadman plans to to use this as grounds to appeal.

But in a separate development, employment lawyers raised the prospect that the ruling that could result in less favourable treatment of younger employees.

New employment laws came into force in the UK only on Sunday as a result of a European directive.

The new laws ban age discrimination in employment and training. They allow employers to give service benefits up to a maximum of five years service but beyond that they have to justify their use in relation to business needs.

More than a third of UK employees are paid on a system based on length of service, most of whom work in the public sector.

Rachel Dineley, an employment expert at Beachcroft, said: "With the UK's introduction of European laws outlawing age discrimination, I expect to see workers firing at their employers with the double-barrelled shotgun of discrimination on the grounds of both age and sex in the future."

She said employers could take comfort from yesterday's decision that pay policies which do indirectly discriminate against women on grounds of length of service cannot readily be challenged.

However, she said that the case was still a partial victory for Ms Cadman because the ruling emphasies that employees can still challenge a service-based pay system.

Anne-Marie Balfour, an employment solicitor at Speechly Bircham, said that any relief felt by employers at being able to continue awarding higher pay on the basis of long service should be tempered with concern about whether it breached age discrimination laws.

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