Thanks to Will Young of Outer Temple Chambers for preparing this case summary
In Equal Pay cases, does the requirement that the comparators be "in the same employment" as the Claimants mean that there has to be some possibility that they could actually be employed at the establishment at which the Claimants work?
No, according to the Supreme Court in the case of North & Ors v Dumfries and Galloway Council.
The requirement in section 1(6) of the Equal Pay Act 1970 (broadly reproduced in s79 Equality Act 2010) that the comparators be employed "at establishments in Great Britain which include [the Claimant's] one and at which common terms and conditions of employment are observed either generally or for employees of the relevant classes" means merely that the Claimants must show that if employed at the Claimants' establishment, however unlikely, the comparators would be employed under broadly similar terms to their current terms.
It is no answer to say that it is not possible (or even feasible) that the comparators would ever work at the Claimants' establishment; the fact that the two classes of employees have to work in different locations is no barrier to equalising the terms on which the work is done. The test in section 1(6) is only designed to weed out cases in which geography plays a significant part in determining the terms and conditions of the relevant employees, not to determine the comparability of their work, which is achieved by other mechanisms in the legislation.