Laurie Webb
From Tardis Wiki, the free Doctor Who reference
Laurie Webb (born 6 May 1924[1]) played Arthur Ollis in the Doctor Who television story The Three Doctors.
He shared his memories of the story on the 156th edition of Big Finish's charity podcast series Toby Hadoke's Who's Round and the documentary Looking for Lennie.
Webb turned 100 in 2024 and is currently the oldest-living actor to have appeared in Doctor Who.