A Southeast Asian war with Singapore still held

What follows if Britain holds Singapore and repels Japan from Malaya?

Singapore becomes a forward Allied base, supporting a northward land campaign and a much stronger naval position in Southeast Asia.

Singapore would become a major forward base. Japanese strikes on Australia and the historical crisis in Burma would become much less likely in this scenario. British and Indian forces could advance north through Malaya toward Vietnam and potentially coordinate with Chinese forces. The Eastern Fleet would operate from Singapore instead of concentrating in the Indian Ocean, while American bombers could support operations against the Philippines and Indochina. Those deployments would force a different Allied command arrangement and make MacArthur's historically separate theater much harder to preserve.