Essentially this was Channel 5's attempt to get more of the sleaze audience. This was "The Crystal Maze" for nudists - it had a series of activities (like a big assault course) that the contestants had to compete over - the twist being everyone was buck naked (save for helmets and safety straps etc).
Even the presenter, children's favourite Keith Chegwin, did it in the buff! It was a horrible thing to watch - indeed quite often the camera would be following someone on the assault course then suddenly lurch off to the side as if the camera man had gotten more than he expected! If the contestants had all been nubile young things then you could have understood why channel 5 would stoop so low but they weren't.
Essentially this was an one-off show (I hope!) that help channel 5 to make the newspapers and get some free publicity. However this was a nasty, voyeuristic piece of trash pretending to be a game show. Even those watching to see naked bodies would have been disappointed.