@Ayxan0
It might come as a surprise to many people not familiar with the UK, but curry, i.e. Indian food, is incredibly popular here, with an Indian restaurant or takeaway in almost any location you visit. In fact, these contribute billions to the UK economy!
Other than that, I guess chips (which the Americans would call fries) are very popular too.
In London, you can find just about any cuisine from around the world, so people tend to eat a very international diet rather than what would be classed as 'local food'. For example, probably people eat a lot more pasta than they do fish and chips.
