Further to my post earlier, Sky have now produced an embeddable copy of Don't Panic's Alan Duncan video. The offending remarks come around 04:30 in:
I know I said before that I'm inclined to believe Duncan's excuse - that the comments were made in jest - but the more I watch the clip, the less convinced I am. Intentional hyperbole - perhaps. A joke - hmm. Either way, it's a stark error of judgement on the shadow leader's part.