Swiss Toni made his first appearance on screen in an episode of The Smell Of Reeves and Mortimer. The character is a creation of Bob Mortimer and Charlie Higson, and this is how he arrived on the show.
He later moved to The Fast Show, but Mortimer receives no writing credits on that, so he may not have been involved in the character’s development.
With the sitcom, it’s Higson and Mortimer listed as the character’s creators in the end credits.