Most EU citizens usually could enter as tourist many Asian countries without holding a visa before landing. This included Malasya, Taiwan, Japan and Korea among others.
Now, given the travel restrictions, where could an UK passport holder land in Asia as a tourist without requiring:
- Visa issued prior to landing
- PCR or medical test
- Been quarantined for XX days upon arrival to its destination.
To the best or my knowledge this is impossible in May 2020. But maybe someone knows one country that allows this.