The counterfactual assumes a French ironclad large and capable enough that the historical Warrior would no longer create decisive psychological overmatch. Britain had considered an armored two-decker in reality, then chose the large-frigate response after intelligence showed La Gloire was manageable. In the altered premise, a French ship of 6,000 to 7,000 tons makes a larger British frigate look like an incremental response. The Royal Navy would still need fast armored frigates for cruising and worldwide presence, so the likely answer is a two-part program. A Warrior-style frigate would fill the global role while a much larger armored two-decker carried the battle and prestige burden. Britain could give priority to rushing the two-decker into service while also building the frigates.
Chapter · 19:03-30:47
A stronger French ironclad could force Britain to build upward
If La Gloire were larger and more capable, Britain could build an armored two-decker to establish a clearer margin of superiority while retaining frigates for global work.