Around about this time every year a fashion feature in some glossy magazine will appear heralding Birkenstock sandals as a new trend for summer. Even devotees will admit they are not the prettiest footwear but they are arguably the most comfortable. They started design life in 1896 when Konrad Birkenstock, who had followed his grandfather into the family cobbling firm and who ran two speciality shoe stores in Frankfurt, invented flexible footbed inserts – based on the cast of a healthy foot in the sand. The inserts were wildly popular, and by 1932 Carl Birkenstock had built on his ancestor’s design, giving podiatry courses throughout Europe successfully expounding his theories of “natural gait”. In 1963 just in time for flower power and hippies – for whom “sandal wearing” is a favoured prefix – Karl Birkenstock took his family’s theories on healthy footwear and designed the Madrid sandal with a deep and flexible footbed, still modelled on that sand cast from 1896. That sandal is still popular today and has spawned a vast range of Birkenstock styles – their upper changing but the base still shaped by Konrad’s footbed.