The Rothesays served throughout the 1960s and 1970s, with Londonderry converted into a weapons and electronics trials vessel in 1975. The successful performance of the Rothesays, and the ability they showed for sustained operation in rough North Atlantic sea conditions during the 1976 Cod War, showed that they were still relevant to the Royal Navy's main role of displaying that it had the ability to restrict Soviet submarine penetration through the Greenland-Iceland-UK Gap during the intensification of the Cold War.
The Rothesays were active between the 1960s and 1970s, with Londonderry repurposed as a weapons and electronics testing vessel in 1975. The Rothesays' successful performance and their ability to operate for extended periods under challenging North Atlantic conditions during the 1976 Cod War demonstrated that they were still relevant to the Royal Navy's primary mission of preventing Soviet submarines from entering the Greenland-Iceland-UK gap during heightened Cold War tensions.