Prior to 1 January 1982, Malaysia had “One Country, Two Time Zones”. “Waktu Semenanjung” and “Waktu Sabah dan Sarawak” were qualifiers that radio and TV time announcements had to be tagged.
Probably many Peninsula folks were traumatized by the fact that they were always 30 minutes “behind time” as compared to their compatriots in the East. Such was the legacy left behind by the British.
I think it was Dr M who provided the final push to achieve this Malaysia Standard Time based on GMT+0800 (which probably delighted Sabahans and Sarawakians).
Singapore had to be persuaded to adopt this MST: with hindsight, this re-alignment of time with China, Taiwan and Hong Kong greatly facilitated economic development of both Singapore and Malaysia.
Good foresight and vision, Dr M, for the “timely unification” of Malaysia.