Favourite: JD Wetherspoon - a British pub/restaurant that is incredibly consistent in what it offers. It's my go-to place when I'm travelling inside the UK.

Least favourite: That's a toss up between McDonalds (I can't stand their stuff) and Subway (I like their stuff, but the standard of cleanliness is pretty poor in a lot of the UK branches, and I've tasted some rather "off" sauces too).