Known as darbies or slangs in the convict ‘flash’ slang language, leg irons came in various shapes and sizes. These bar link leg irons weigh about 7 ½ pounds (3.4 kilograms), and were worn by troublesome convicts working in iron gangs, or to restrain men awaiting trial on serious crimes. This type of leg iron with long bar links is seen in images of convicts in England from the early nineteenth century, suggesting that this set was manufactured there, rather than in the colony.
The leg irons that convicts wore on the transportation ships were removed on arrival in the colony, but plenty of convicts soon found themselves back in irons. By order of a magistrate, leg irons were fitted onto the ankles of those who committed secondary crimes, such as running away, trying to escape the colony, highway robbery or selling government property. They were then put to hard labour in iron gangs for several months or longer - one of the worst punishments that could be given to convicts. These men had to wear special trousers that buttoned up the sides, so they could be taken on and off around the leg irons.
Leg-irons were made by convict blacksmiths at Sydney’s lumberyard after those sent from England proved to be inferior and easily slipped off. Irons were affixed to and struck off convicts’ ankles by the blacksmiths.
The clanking of the fetters had a dismal sound ; but the men seemed to walk lightly along… some of the worst characters had rods of iron fastened up betwixt the limbs.
John Banks, Australia and the East, 1840, 127.