The County group was laid down between 1924 and 1927, so the twenty-year rule pushed replacement into 1944 to 1947. The Hawkins-class ships dated from 1916 or 1917 and qualified under the sixteen-year rule. Hawkins, Raleigh, and Cavendish could therefore have been replaced in 1932, with Effingham following in 1933. County or York derivatives already offered workable design paths. Governments had designs and treaty permission, but were unwilling to fund construction.
Notable Point · 2:27-5:28
County cruisers, Hawkins, and replacement choices
The 1924 to 1927 County group could not be replaced until 1944 or later, while the older Hawkins class offered an earlier opportunity to modernise.