Wilson v Health and Safety Executive

Although the law requires employers to pay men and women equally for work rated as equivalent under a valid job evaluation scheme, they do not have to justify a difference in pay if it is due to a length of service award. In Wilson v Health and Safety Executive, the Court of Appeal has now said, however, that employers can be required to justify the “use of a length of service criterion as well as its adoption in the first place”.

Basic facts

Ms Wilson (a band 3 inspector) made an equal pay claim in July 2002, comparing herself with three other inspectors in the same band. Although their jobs had all been rated as equivalent in a job evaluation study carried out in 1995, the male inspectors were paid more than her partly because they received length of service increments after ten years in the job. Ms Wilson argued that the employer could not justify the length of service payments because staff were fully proficient at their job after three years.

Tribunal and EAT decisions

The tribunal decided that the length of service criterion had a disparate impact on female employees, but that because of the decision by the European Court of Justice (ECJ) in Danfoss, the HSE did not have to justify it.

Ms Wilson’s appeal to the EAT was then stayed until the ECJ had come to a decision in the similar case of Cadman v HSE. It said that although employers did not, as a general rule, have to justify length of service as a pay policy objective they would have to if a worker provided evidence that cast “serious doubts” on whether it was appropriate.

The EAT then decided that tribunals should be allowed to look at whether an employer could justify the way the length of service criterion had been applied, but that claimants had to provide evidence that raised really serious doubts about its use.

Court of Appeal’s decision

The Court of Appeal has now said, as a result of the decision in Cadman, that employers can be required to justify the “use of a length of service criterion as well as its adoption in the first place”.

But when does the burden of proof pass to the employer? The Court of Appeal has said that the test of “serious doubts” which the ECJ applied in Cadman was only a preliminary test to act as a filter on claims before a trial. It was not applicable, therefore, once the trial had taken place and liability had been found.

In order to pursue a case, the Court said that employees would have to show that they had evidence that the general rule (that a length of service criterion did not have to be justified) did not apply. That evidence would have to create “serious doubts” in the minds of the tribunal that the adoption or use of the length of service criterion was not justified and/or was disproportionate.

Finally, the onus of proving justification remained with the employer. “The employee has only to show that there is evidence from which, if established at trial, it can properly be found that the general rule ... does not apply. This does not amount to a switch in the burden of proof, it is merely a sensible evidential requirement to ensure that the complaint has some prospect of success. ... It makes good sense that there should be such a requirement to avoid unnecessary claims”.


In future, to pursue such a case, employees will have to do no more than show that their claim has some prospect of success by demonstrating there is evidence, if proved at trial, from which it could ultimately be held that the creation or use of length of service cannot be justified and/or is disproportionate. The burden of proof in relation to objective justification, including showing proportionality, remains that of the employer