Thousands of racehorses have been slaughtered in abattoirs in Britain and Ireland since the beginning of 2019, according to figures obtained by BBC Panorama.
Animal Aid, which campaigns for an end to horse racing, set up covert cameras in one of the few slaughterhouses in England licensed to kill horses.
Independent veterinary experts said the methods of slaughter caused unnecessary suffering.
The abattoir said it did not accept any form of animal abuse.
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