I am not sure everyone is speaking the same language here. A UK gallon is 25% bigger than a US gallon, so UK mpg is correspondingly higher. Also the testing is presumably different, so numbers measured in the UK are not comparable with US numbers even taking account gallon size differences.

I assume the questioner is asking about US mpg? The Prius was there for sure in US mpg (just, at 51mpg), not sure about others.