“If the heel is continually in a raised position, then it shortens the calf muscle. All the weight is forced on to the metatarsal head and this can cause bunions, corns and calluses; prolonged wear also causes degeneration of joint function,” says Dr Charlotte Hawkins, a specialist in biomechanics and gait. “Overall, it is not a great idea.” So what is an acceptable heel height? “One or maybe two inches.”