Sapphire is a relatively common material in high-end watchmaking.
Once the home of light industries such as brewing and watchmaking, many of the old commercial buildings have recently been converted into apartments.
In 1905 Hans Wilsdorf, a 24-year-old Bavarian who learned watchmaking in Switzerland, set up a business in Hatton Garden to distribute watches.
"No one even thinks of watchmaking as a possible profession these days," he said.
