Why British Type 42s lacked antiship missiles

Why did Royal Navy Type 42 destroyers lack antiship missiles when Argentine Type 42s carried them?

Britain saved the money; Argentina paid for a different weapons fit on the same basic destroyer design.

The British omission is explained as a decision to save money. Treasury cost-efficiency review is described as the mechanism for deciding whether equipment was worth funding. The Argentine fit demonstrates that the hull could carry the additional weapons. The explanation identifies procurement spending as the cause without supplying a particular cost paper or decision date.