A shocking discovery at a building site in England led volunteers on an animal rescue they weren’t sure would be a success.

A call from a member of the public led volunteers from the British Horse Society to a grim discovery.

The building site in East Durham, looked like it had been abandoned with rubbish and debris everywhere and there lying in the mud they found what they first thought was a dead horse.

She was filthy and emaciated but on a closer inspection they found the horse, which they named Heidi, still breathing.

It was one of the most severe cases of neglect they had ever seen and without hesitation they stepped into action.

“It took five people to lift her to her feet,” said the spokesperson of Here 4 Horses Equine Charity.

It turns out the owner of the site had called someone in to remove the body of the horse, he believed was dead.

“Whether he thought she was already dead is irrelevant—she had been subject to the most awful suffering, ” Wendy Suddes from the nonprofit Here4Horses told Bored Panda.

The nonprofit did all they could to ensure this sweet horse survived but it was touch and go as she couldn’t even stand up when she was first rescued.

“The early days were touch and go, as we dealt with her serious weakness and such a low blood protein level that a plasma transfusion was required,” Wendy said.