Nick Upton has worked as an animator on numerous stop motion productions over the years, including A Close Shave, Gogs and Chicken Run. Unusually, however, he has also produced a large amount of animation from in front of the camera: Upton is the only person I can think of off the top of my head who has ever been a regular performer in pixilation.
His best-known work in this role is in the TV film The Secret Adventures of Tomb Thumb, in which he played Tom's father. But he has appeared in a number of other pixilation projects, albeit some which have been forgotten.
In the eighties, Nick Upton starred in an elaborate pixilated advert for the Manchester Evening News, which I covered recently...
...and he later worked with Frank Passingham of Bolexbrothers to create these linking sequences for Treble Top, a 1992 BBC programme showcasing the work of Peter Lord, Daniel Graves and Ken Lidster.
Back at Aardman, it was Upton's hand that represented the Creator in Peter Lord's Adam. Upton was also involved in the pixilated series Angry Kid, although I cannot confirm his exact role.
And finally, IMDB credits Upton with directing two nature documentaries for television: Grüne Insel im Taifun, an Austrian film co-directed by Michael Schlamberger; and Beetlemania. However, as IMDB is prone to conflating different people with the same name, I cannot confirm if this is indeed the same Nick Upton.