Why the Singapore strategy failed in the worst sequence

If Britain was preparing for a Pacific war, what went wrong strategically before the fall of Singapore?

The worst possible sequence of enemies stretched British forces across the Atlantic and Mediterranean, leaving an exposed, under-strength deterrent in the Far East.

War against Germany first drew resources toward the Atlantic, and Italy's entry increased Mediterranean demands before Japan attacked. Sending only two capital ships east revealed the limit of available reinforcement instead of presenting either overwhelming force or dismissive cruiser-level confidence. A larger concentration in the Indian Ocean could have supported either theater while presenting a more credible deterrent. A sound peacetime concept can fail when opponents enter the war in the least favorable order.