Why pre-treaty experimental carriers gave Britain flexibility

Building every carrier after the Washington treaty would lock Britain into early choices, whereas pre-treaty experimental ships could be replaced without consuming the same long-term tonnage.

Question

What if Britain built only new carriers after the Washington treaty instead of converting ships?

Short answer

It could do so, but post-treaty ships would lock up carrier tonnage for years, while the older experimental fleet gave Britain more freedom to replace designs as it learned.

Notes

Britain's early carriers were experimental ships built or launched before the treaty framework settled. Their status helped the Royal Navy replace or supplement them during the 1930s as operational lessons accumulated. A newly built post-treaty carrier would count firmly against the allowance and remain in the force structure for a long time. Converting or retaining experimental tonnage therefore gave Britain design flexibility that a fleet of early purpose-built treaty carriers would have surrendered.