Stephen Le Page was a Perseus Corporeal who had disguised himself as a human in the 21st century. He was assigned to work with Steven Page, and chose the name "Stephen Le Page" on purpose to annoy Page.
Le Page and Page imprisoned the Third Doctor and Jo Grant when they were apprehended for not having PANs. They placed implants in the Doctor and Jo, designed to keep track of them. Le Page explained Perseus' mission, which was to gradually convert all humans on Earth into Corporeals. Le Page revealed his plans to the Doctor only because he knew the implant would cause the Doctor to forget the conversation. Le Page was killed by one of the humans he had tried to convert. (PROSE: Carpenter/Butterfly/Baronet)