This post is a nice summary of the Royal Navy’s frigates, destroyers, and cruisers from the Second World War through to the present day:
Before the Second World War the RN was predominantly a “cruiser navy”, holding down a range of global deployments with its 15 heavy and 41 light cruisers. These ships had endurance and combat power at the core of their designs, each could operate alone for extended periods, effectively defend itself in most circumstances and demonstrate the interest or resolve of the government in a particular region. The ensuing World War and the Cold War radically changed the type of warships the RN needed. Instead of cruisers built for endurance and complex warfighting the navy built a profusion of smaller frigates and destroyers, mainly to guard convoys and fight submarines close to the UK and in the North Atlantic. To carry out these tasks the navy could make do with smaller, cheaper, ships with relatively shorter legs and far less ability to act independently in high threat environments. Trade-offs like these were made in order to ensure the navy got enough escorts to protect the convoys which would be vital to Britain’s survival in the event of a war; and to hunt the Soviet ballistic missile submarines that threatened NATO. These were ships designed to act as part of a military system that would defeat the threat posed by hostile submarines. This system also included land based aircraft, anti submarine helicopters, aircraft and helicopter carriers and the enormous US/NATO SOSUS fixed sonar array. The Leander class is probably the most famous example of these sort of light frigates, operated by the RN into the early 1990s. When the immediate and pressing threat from submarines operating in the North Atlantic, be they German or Soviet, ceased to exist so the naval forces the UK had constructed to defeat them also fell by the wayside. These ships were, broadly speaking, a product of their time and a deviation from the much older structure that had served the RN well for centuries. This structure consisted of a core “battle fleet”, made up of capital ships; mainly there to act as a deterrent, supported by powerful forward deployed cruisers that conducted most of the day to day activity.
By modern standards almost all of the cheap and numerous frigates and destroyers of the past, even the excellent Leanders, would be classed as lightly armed corvettes. The simple fact was that these cheap and numerous ships sacrificed a lot of capability in order to achieve the affordability necessary to build them in numbers. They were still recognisable as frigates built in the convoy escort mold. Similarly the Type 42 anti-aircraft warfare destroyers, in service from the mid-1970s, were also a design that compromised range and armament for numbers. At only 3500 tonnes the Batch 1 Type 42s were clearly a very light and economical design. When compared with their American counterparts, the 8000 tonne Spruance class, it’s clear that these ships sacrificed range and armament for economy and numbers. Both the Leanders and the Type 42s are recognisable as frigates and destroyers, light warships designed to act in groups and alongside other warships, auxiliaries and aircraft to be effective in combat. The closest the RN came to “cruiser” designs during the Cold War were the eight County Class missile destroyers commissioned in the early 1960s and HMS Bristol, the sole survivor of the pre-1968 carrier escort programme. While these destroyer classes were cruiser-like in some aspects, they carried a far more comprehensive armament and had a greater range (in terms of fuel) than their contemporaries, they lacked the self-sustainment ability, protection, survivability and range of “true” cruisers. While Bristol was initially labelled a light cruiser by Jane’s, the Royal Navy always saw her for what she was: an oversize missile destroyer with the similar limitations to the navy’s other destroyers.
With the later Type 22 and 23 frigates the RN moved to fewer, more individually capable, platforms. This change was partly necessitated by the introduction of a new generation of bigger towed array sonars which required larger ships to operate effectively. Despite their greatly improved self defence ability, achieved by fitting the Sea Wolf point defence missile system, these ships were still designed to be expendable escorts and lacked the endurance of cruisers. That said, these two classes signalled the start of the navy’s shift from a fleet of numerous, small and cheap escorts to fewer, larger ships capable of independent operations in a high threat environment.