Sex discrimination: Meaning of "considerably smaller" proportion

In London Underground Ltd v Edwards (No.2) [1998] IRLR 364, the Court of Appeal holds that a female train driver who was unable to comply with new rostering arrangements imposed by her employer was indirectly discriminated against on the ground of her sex. The proportion of women in the pool for comparison who could work the new roster (95%) was not too large to leave room for a finding that such proportion was "considerably smaller" than the proportion of men in the pool who could do so (100%).