Fun:Argument from oh bloody hell that was years ago
Argument from "Oh, bloody hell, that was years ago," is a possible logical fallacy outlined by YouTube user Coughlan666. It means assuming that because someone (particularly a public figure, trying to gather support of his cause) hasn't expressed an insane or offensive opinion for a long time, quotes can no longer be used against him. This can, however, devolve into assuming that people never change their minds.
Whether the idea is a true fallacy or not, formal or informal, is debatable, but its use in defending the BNP or other miscreants is known. As coughlan666 points out "so fucking what if they said it last Tuesday?".
There is probably a valid use of this defense in the case of some intervening event that shifts the nature of the debate (as sometimes to frequently happens when the quote is more than 15 years old), such that it is worth checking if the person's position has actually shifted. That being said, the defense is probably fallacious if nothing has changed in the intervening years, and the defended has done nothing to renounce the opinion in question.