SteveON: They don't have to remove the ad, the ASA hold no legally binding authority.
Actually, they kind of do. The ASA was formed by the advertising industry voluntarily under the threat of government regulation. Basically, the ASA exists so that the government does not create a legally binding authority, as the advertising industry would prefer to control their own regulation (the alcohol, gambling, etc, industries didn't think far enough ahead to pull this stunt).
So, yes, Telecom did have to pull the ad.