Was Waldo a reference to any true story?

The initial inspiration was a British band called Gorillaz.

According to this interview with the show's creator Charlie Brooker, the Waldo character was initially based on a virtual band called Gorillaz. The band exists only as a cartoon, though real musicians are behind the music. Brooker states that he had an idea of some character like that actually running for office. He was fascinated by the idea that such a politician, not being a real person, would be scandal-proof. He also states that the character was inspired by British politician Boris Johnson because like Johnson, Waldo doesn't act like a politician by trying to be inoffensive and dignified all the time. Another source of inspiration was a comedian who was elected as the mayor of Reykjavik.