Whose bag Where is it going What to do with it Answers to these questions led to the innovation of the baggage tag when it first made an appearance on the steam ship. Apart from being lovely little examples of advertising design, they bore the passenger&rsquos name, destination and whether the bag was &lsquoWanted in Stateroom&rsquo or &lsquoHold&rsquo or &lsquoNot Wanted&rsquo.

When the bag tag mutated to being used in railways and then aviation, it began to carry some additional details such as weight, which became very common on airline tags by the 1920s.

The modern, automated tag is a marvel of design. Look at the brief required to be resistant to cold, heat, sunlight, ice, oil and moisture. Also, it needed to be flexible, cheap and disposable &mdash and impossible to tear. To top that, it had to be easy to attach, but impossible to detach accidentally. The winning material was a complex composite of silicon and plastic and the design was the deceptively simple loop tag that appeared in the early &rsquo90s.

The future of tags is radio-frequency identification or RFID, which allows bags to be identified wirelessly. Hong Kong used it from 2008 and frequent fliers on Qantas are given tags that&rsquoll let them check in their bags on domestic flights. Widespread adoption of RFID is inevitable, even if some distance away.