Once you've tracked where your egg came from, here's what to do with it once it's home.
Fridge or room temperature?
The Food Standards Agency's advice is to keep eggs somewhere cool and dry, ideally in the fridge, and to avoid moving them between warm and cold repeatedly -- the temperature swings cause condensation on the shell, which can let bacteria in. Unlike in the US, UK eggs don't have to be refrigerated before you buy them: British Lion-marked eggs come from flocks vaccinated against salmonella, which is the main reason UK guidance is more relaxed than American guidance on this. Once you're home, though, the fridge is still the safer bet.
Best before, not use by
UK eggs carry a "best before" date rather than a "use by" date, and that date can be set no more than 28 days after the egg was laid. A best-before date is about quality, not safety -- food is usually still fine to eat after it if it looks and smells normal, though eggs are best used while properly fresh for both taste and texture. There's no official rule for exactly how many extra days you get past the date, so if in doubt, use the checks below.
The float test
It's not a pass/fail safety test on its own -- but combined with a look and a sniff once cracked, it's a genuinely useful sense-check.
Related reading
Curious why UK eggs don't need refrigerating before purchase in the first place? See what the Lion stamp means. Ready to actually use them? See our egg recipes. Or head back to the tracker to find out where yours came from.
Sources: gov.uk -- safe storage, handling and use of eggs; gov.uk -- best before and use-by dates; egginfo.co.uk.