Paul Yarrow started his personal crusade on the streets of London, where a lot of television reporters apparently do a lot of standups. He noticed that video photographers were constantly shooing him out of the way and never wanted to interview him for stories.
So, he started his plan in motion, and set out to appear in the background of as many television reports as possible. In some circles, it's called "Photobombing."
So far, Yarrow's done about 100 of these "guest" spots.ABC News Nightline report
However, it appears the "tubby man in the woolly pully" has appeared in his last reporter standup. According to this report on thisislondon.com, he is going to stop his practice because he's become the story, rather than his point: Television reporters need to stop interviewing only people who are good looking, and start talking to everyone.