UK: It's illegal to sell washed eggs
US: It's illegal to sell unwashed Eggs
OTOH, It's cheaper for the producer to keep chickens in worse conditions, wash the eggs removing the protection and make consumers keep eggs in the fridge!
USDA mandates egg washing to combat salmonella. But the washing process also destroys the egg's outer most protective layer, the cuticle. Thus American eggs must be refrigerated, unlike almost everywhere else in the world.
In the UK, all chickens are already vaccinated against salmonella so their eggs don't need to be washed, nor refrigerated. This has a couple of benefits:
1. The cuticle remains intact, thus the egg is naturally protected against contamination during transport and storage.
2. Refrigerated eggs undergo temperature swings during transport, causing moistures to collect, which could lead to harmful bacterial growth.
3. A botched washing job leads to excess moisture and thus bacteria growth, and is worst than no washing job at all.
That's why it's actually illegal for the farm to wash the eggs in the UK.
I'm sure a lot of it does have to do with conditions though. If you have to wash the eggs anyway, you can keep them in factory conditions, and wash off all the shit. If you're not allowed to wash the eggs, then you tend to be a bit more careful, and keep them in better conditions.
In the UK on the other hand it is the exact opposite. You can fill your own LPG tank no problem, but I have not seen any pistols with the locks on them, because "it would be dangerous, what if you leave it in and forget about it??". It's just a matter of interpretation, a thing that is seen as dangerous in one country is completely fine in another.