From 1800 until the late 1930s, the ownership of pets in London increased to huge levels. Especially cat ownership, as cats were favoured to contol the mice that invaded every home, and rats too. In the year 1861 alone, it was recorded (by Henry Mayhew) that around 300,000 cats lived in London homes.
This was an opportunity for a new trade, selling pet meat. Starting out by wandering the streets with carts or baskets, pet meat sellers soon established regular rounds. After WW1, some traders transferred to market stalls, or rented shops.
They sold horse meat, which was widely available due to the hundreds of worn-out or injured horses slaughtered each day in London. Generally considered to be unfit for human consumption, and often tainted or spoiled, this meat was cheap to buy, and readily eaten by cats and dogs.
There were so many pet meat sellers in the city, they attracted the attention of street photographers who captured this lost trade for us, and preserved the history of it.