Un-banned ad of the week, this ad depicting Nick Clegg and Nigel Farage caught in the middle of... eh.. debating, and coupled with with the headline "WHO'S THE BEST MASS DEBATER? CLEGG 6/4 FARAGE 1/2 ..." seems to suggest that they're actually masturbating. Two people complained!
Paddy Power responded, and said that although the ad made use of a double entendre, it was "light hearted and tongue-in-cheek" and intended to generate interest in a humorous and irreverent way. Because knob jokes are funny, you see. At least their target market thinks so. Paddy Power "regrets causing offence" but also noted that since only two people complained, widespread offence had not been caused.
The Advertising Standards Authority said that not everyone may share Paddy Power's sense of humor, the fact that the ad appeared in a newspaper aimed at adults, and during the time when there were TV debates between the two men, the context made it unlikely to cause offence to a widespread degree. Thus, the ad is not banned, though terrible puns like that should be a punishable offence IMHO, your milage may vary.