The missed British SSGN opportunity

Did Britain have anything like the US cruise-missile submarine Growler?

No dedicated equivalent was built, though a cruise-missile version of a Resolution-class boat was considered and might have offered useful continuity and capability.

Britain never built a dedicated cruise-missile submarine and instead launches Tomahawks through attack-submarine torpedo tubes. Before cancelling a fifth Resolution-class hull, planners considered alternative uses that included an SSGN role. A dedicated conversion might have carried several dozen contemporary cruise missiles, though finding a suitable weapon in the late 1960s was a serious obstacle. Building it would have preserved industrial continuity and opened a conventional strike line alongside the ballistic-missile deterrent.