In 35 years at sea, HMS Iron Duke only ever fired her guns in anger a handful of times. She did so to hit a gun battery during the war against Colonel Gaddafi in Libya in 2011, and before that while seizing drugs in the Caribbean in 2009. For a Type 23 frigate, designed in the 1980s to take on the might of the Soviet navy, it was small-scale stuff. But at a time when the Cold War seemed long over, it was a reminder that a well-resourced navy still had its uses. Yet for many years during those more peaceful times, that reminder was ignored. Rather than building replacements for the 15-strong Type 23 fleet, each of which had an intended 18-year lifespan, the order books were kept empty. That meant frigates such as the Iron Duke, which launched in 1991, were kept at sea long past their use-by date. Last week, it was revealed that the ship had quietly been withdrawn from service in October – despite having had an almost five-year, £103m …