Why doesn't Canberra have any billboard advertising?

Primary school teacher Sandi Lees appreciates the fact that her city has very few billboards. But she wants to know why that's the case, and more importantly, whether it's likely to be the case for many years to come. ACT political reporter James Fettes already knew a thing or two about the nation's capital and it's relationship to billboard advertising, so he went looking for the answer.