Ten years of rhetoric from Labour and Conservative (and Lib Dem) governments about disability scroungers was corroded into sludge in ten minutes by one of its principal architects. He described the budget as "deeply unfair" and unequivocally opposed the welfare cap. The terms of the UK debate on disability benefits have been changed out of all recognition in the last 48 hours.
I do not warm to IDS who, if he is sincere now, should never have taken the job in the first place. But truths have been told by someone I did not expect to tell them.
(See also: Stephen Bush: "Think Iain Duncan Smith's resignation is a masterstroke? Sadly, he's not that clever")