By the 1980s, Thomas Mercer of St Albans had made almost a third of all chronometers in history – including that used by Ernest Shackleton to navigate his men to Elephant Island and eventual rescue during the Trans-Arctic Expedition of 1914.
Less often encountered are Mercer table clocks that were made to equally high standards well into the post-war era. This 10in (24cm) eight-day mantel chronometer housed in a burr-walnut and ebony-strung case, numbered 1231, probably dates to c.1975.