Thanks to modern science, you will no longer have to wonder exactly when your soft-boiled, medium-boiled or hard-boiled egg is ready. Why's that? Because the egg is going to tell you itself! Okay, so it's not going to shout out and say "Hey, I'm ready!" but it will have magical (aka science) invisible ink that turns black the minute it is ready. You just have to decide which sort of notification you'd like before you purchase your eggs.
Now if you're wondering why they're doing this:
A spokeswoman for Lion Quality Eggs, the [British Egg Information Service]’s quality assurance scheme, said: “We had a lot of inquiries. We said OK, this is a big issue — people can’t even boil an egg.”
So there you have it. The eggs will hit UK markets this fall. No word on whether or not they'll cost more.
Source: Times Online