Legal Queen Naomi Cunningham with a further insightful comment on case-by-case (and the concept of "bright line rules") on LI:
I haven't had time yet to read For Women Scotland v Scottish Ministers (no.3) properly yet, but one point that has already jumped out at me is the extensive and robust treatment of "bright line rules". The exclusion of men from women's prisons is a bright line rule to which no exceptions are permissible, and the court is clear that that does not render it unlawful.
A constant insistence on "case by case assessment" has bedevilled the law in this area for years. Public lawyers in particular appear to have contracted a bad case of bright line phobia. I've suspected for a while that this is attributable to concept creep from the rule against fettering of discretion.
I'll explain. If legislation gives you a discretion to exercise, you're not allowed to decide to exercise it always the same way, or substitute hard-and-fast rules for the exercise of that discretion; that's "fettering" your discretion, rather than exercising it as you were told to.
My suspicion is that that perfectly sensible and well-established rule has left lots of public lawyers with a kind of unthinking nervousness about hard-and-fast rules, and that has morphed over the years into an unfounded belief that bright line rules need some very special kind of justification to be lawful.
When you think about it, that's nonsense. The world bristles with bright line rules. You can't buy alcohol in a pub or vote until you're 18. Seatbelts must be worn. No entry to the building site without a hard hat. No-one under 5' may use the fairground ride. No peanuts in the kitchen. No climbing on the roof of the school. (I've always thought this last rather a shame - why aren't primary schools designed, low-rise, with rope ladders up to the roof and slides and zip-wires back down? But I digress.)
Sometimes legislation confers a discretion, and when it does, it has to be exercised without recourse to hard and fast rules. But often legislation, or someone else with power to make rules in a particular situation, lays down bright line rules instead, and that's perfectly fine.
"Women only" is the kind of rule that normally makes no sense at all unless it's treated as a bright line rule. That's because if you tell women this space is for women only, they need to be able to be confident that they won't meet men there. As I've said before, it's like peanut-free meals: you have to leave the peanuts out, or it's not peanut-free.
https://www.linkedin.com/posts/naomi-cunningham-3332a716_i-havent-had-time-yet-to-read-for-women-activity-7474001102972059648-e5Bx