Fortnum and Mason
One of the defining parts of the Industrial Revolution was the rise of ready-made fashions and pre-packaged foodstuffs, and on the forefront of the trend was the posh department store, Fortnum and Mason. When the first steam-powered factories were just starting the churn out their wares F&M was already in business, and it continues to be a mainstay of the stores on Piccadilly today.
They made a splash at the Great Exhibition in 1851 where they won first prize for their imported delectable desserts and dried fruits. In addition, when Henry Heinz (best known nowadays for ketchup) wanted to market his canned baked beans in the UK, he took his wares there. Within a few years, baked beans had become an important part of the British diet.
In literature, F&M are best known for their picnic hampers and several Victorian authors including Charles Dickens and Wilkie Collins made mention of their characters enjoying a luxurious feast. I am also reading The Difference Engine right now, and the day after snapping shots of the whimsical window displays below I read a passage where the protagonist passed by this prestigious store on his way to buy a wedding gift for his sister. Today, you can still visit and stroll through the heaps of lovely packages tied with bright ribbons and peruse the fanciful fudge of the dessert counter.
As with many luxury goods stores, the prices are steeper for things such as tea and cookies than at a normal grocer, but the ambience alone is worth a stop in at the store, or at least a meander by the window displays!