Legend has it that fried fish shops, spreading north from the south of England, merged with fried potato shops descending from Scotland. The fish is traditionally Atlantic Cod or Haddock, battered or breaded -- and the chips are slab cut potatoes. All deep fried. Simple, fresh, hot.
As with a lot of English fare, fish and chips became a standard staple with the working masses. The emergence of trawl fishing and rail transport in the second half of the nineteenth century allowed the North Sea's fresh catch to remain cheap. Mass distribution, then popularity. Chips may also have appeared at the same time -- first mentioned by Charles Dickens in his A Tale of Two Cities. Welcome the Industrial Revolution, Capitalism and their benefits (most frequently maligned). Yes, there are many ways in which labor is rewarded. In this case perhaps, symbolized by a bit of malt on one's blue collar.