At the beginning of the second world war, before a single shot had been fired, the British set about killing hundreds of thousands of their own pets.

The British pet massacre is one of the stranger tragedies of WWII, a footnote that gets lost amongst all the human devastation that followed. In 1939, the British government formed the National Air Raid Precautions Animals Committee to decide what should happen to pets as the war commenced. The fear was that as the government was forced to ration food, people would either share their rations with their pets or simply leave them to die, inhumanely, of hunger.

Believing neither of these options to be palatable, they decided on the next best thing: urging people to destroy their healthy pets post-haste. 

In a pamphlet distributed amongst the population, they suggested that anyone with pets consider relocating them to the countryside (not a euphemism) or "if you cannot place them in the care of neighbors, it really is kindest to have them destroyed". Though the message clearly highlighted that they should seek a new home for the pets first, it was undermined somewhat by the fact that opposite the message was a full-page ad for a bolt gun labeled "the standard instrument for the humane destruction of domestic animals".

When war was declared, pet owners dutifully lined up in their hundreds of thousands to get their beloved pets destroyed. 

"Our technical officers called upon to perform this unhappy duty will never forget the tragedy of those days," the founder of the People's Dispensary for Sick Animals said of the time.

Within a week, over 400,000 dogs and cats had been put down, a quarter of London's pets. Queues outside one animal shelter reached half a mile long, full of people waiting to destroy their animals, and crematoriums became backed up with corpses, as they couldn't operate at night due to blackout orders. When suitable graveyards ran out, half a million pets were buried under one meadow. In total, over 750,000 pets were killed.

People thought they were doing the right thing, but it quickly became apparent that, as was reported in The Times, “there is daily evidence that large numbers of pet dogs are still being destroyed for no better reason than that it is inconvenient to keep them alive – which, of course, is no reason at all, but merely shows an owner’s inability to appreciate his obligations towards his animal.”

Those that escaped the initial frenzy mostly survived until the end of the war.