In the Sheffield directory (1774), Martin Briddock was listed as a maker of spotted knives, which sold for 16 shillings (about 75 pence) each.  His background is obscure, though he worked at Malin Bridge and may have become a Freeman in 1761.   The directory in 1787 listed Martin Briddock, a spotted knife manufacturer, at Wisewood, using the trade mark ‘GHUR’.   Confusingly, in the same directory Martin Briddock was listed as a pen and pocket knife maker at Lambert Street, using the trade mark ‘BRIDDOCK’.  In 1797, Martin Briddock was listed again as a pocket knife cutler at Malin Bridge.  His later life is unknown.