How to get those UK looking License Plates?

So the other day I was driving and I saw some UK looking License plates on a car. The car was obviously a Texas registered vehicle though...and I've seen them on about 4 cars already. Perhaps Im late on something? or Maybe they're something else? Maybe a stupid question but how do you go about getting them? I must say They look pretty cool.

Mods: If this belongs in the Car section feel free to move.
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