Returning to Britain in the mid-1960s, Wilkin provided the voice of Virgil Tracy for the second series of Thunderbirds following the departure of the character's original voice actor, David Holliday, in 1965.
After David Holliday's departure from voicing Virgil Tracy in 1965, Wilkin returned to Britain in the mid-1960s and took over the character's voice for the second series of Thunderbirds.