The UFC's heavyweight title is disputed. England's Tom Aspinall has been interim champion for 535 days and counting.

Tom Aspinall ... Barao Aspinall’s journey to this record began with a thunderous 69-second knockout of Sergei Pavlovich at UFC 295 in November 2023, claiming the interim title on short notice ...

The UFC's heavyweight title is disputed. England's Tom Aspinall has been interim champion for 535 days and counting. Now, Aspinall is the longest-reigning interim champion in UFC history.