Why was David Holliday replaced with Jeremy Wilkin as the voice of Virgil Tracy for the last six episodes of THUNDERBIRDS? The reason for the departure of voice artist David Holliday from the highly-successful THUNDERBIRDS prior to the last six episodes of the series seems to be cloaked in mystery. Gerry Anderson says that Holliday asked that his contract be renegotiated between shooting blocks of THUNDERBIRDS and wanted too much money and perks. Holliday admits he asked for his contract to be renegotiated but says it was because he was offered better paying work and wanted his duties restructured.

In any event, Holliday was released from his contract and actor Jeremy Wilkin (who later went on to provide voices in CAPTAIN SCARLET AND THE MYSTERONS, JOE 90, and THE SECRET SERVICE, and to play the Skydiver navigator in UFO) took over the role of Virgil Tracy for the final block of THUNDERBIRDS episodes and the THUNDERBIRDS movies. Holliday today is alive and well and living in the U.S., making a living primarily as a stage actor, especially in musicals.