The urban fox is believed to have climbed onto the roof and into the hospital during construction work.
The RSPCA was called to collect the startled animal, which was not injured by the fall, but the rescue was called off when the fox escaped through an open window.
“It’s not something I’ve ever heard of happening before,” a spokesperson said.
ecurity has now been improved in the 1970s tower block to make it more difficult for animals to gain access.
A string of suspected fox attacks have been reported in London in recent years, prompting warnings for well-meaning residents to stop leaving food out for the animals.
A baby boy had his finger bitten off by a fox in Bromley, south-east London, in February last year, leading Boris Johnson to label them “a pest and a menace”.