U2 frontman Bono has urged world governments to keep their promise to cancel third world debt. The campaigning rocker is concerned that politicians aren't sticking to the G8 agreement to double African aid to $47 billion (GBP24 billion) by 2010. Speaking at the World Economic Forum in Davos, Switzerland, the Beautiful Day rocker says, "There were some serious promises made. "The cheques were signed but as you know, politicians like signing cheques but they don't like cashing them. "Two years on, it's time to take the temperature. If those promises are not kept ... it will make a generation of cynics. I don't believe that's going to happen, I am optimistic we're going to get through this."