The election for London Mayor of 2011 pitted Boris Johnson against Ken Livingstone. Boris was popular (my how times have changed..) and had the support of all the newspapers. Ken didn't even have the support of his own party.
In the end we lost. But we gave Boris a scare taking Ken from 12 points behind to only 2 points at election time.
A key part was our party political broadcast. We knew it was powerful for two reasons. Firstly, it made Ken cry at his own press conference. Secondly because of the all out attack it received to try and undermine it. Even journalists from our own trade magazine tried to discredit it. Did i mention that that particular magazine is owned by Lord Heseltine?
Post the election we ran an ad for the agency to highlight the power of emotion.