Didn't they already try this with earth shoes?

Susanne Birkenstock, ex-wife of the shoemaker, is marketing her own shoe using the Birkenstock name, which is leading to all sorts of strife amongst the Birkenstocks.

Susanne's shoes have negative heels, which she says, improve the posture.

"My shoes elongate and tone the muscles, and they are anti-cellulite. It is like walking on soft sand," says Susanne, getting into her marketing stride now that, mercifully, we are once again sitting down. "But zay are not just a healthy shoe, also zay are elegant."

Whether leopard-printed or jewel-encrusted, sandals remain comical and summery, so Susanne, who wants year-round sales, has been adding to the range. This spring, we have the trainer, which is said to stretch the muscles that exercise contracts. In autumn, she will unveil "healthy" high heels. Their design has been a challenge.

"High heels are very uncomfortable, perhaps because most designers are men and they never have to wear them," she explains. "The heel is normally on a slope so the whole weight goes down to the toe. I am adjusting the weight so it goes to the heel and the middle of the foot, so you don't have to arch your back.

"I am thinking about the whole body. I work in a laboratory with a scientist who designs for astronauts who need to exercise in zero gravity. Sometimes, just a millimetre makes a big difference. "

But the back-arching and the trippy walk are part of what make high heels sexy sorry to say. Then there's the way high heels make your ankle look smaller and your calf look shapelier. And a couple inches in height don't hurt either.

The reverse heel is not a new phenomenon. And whatever name you sell it under, it's still ugly.