Some people say that the greatest threat to that irony evaporating (that is, universal credit being successfully implemented) is the IT system. Others say it's intransigent or incompetent officials at the DWP. But there's a greater threat than either of those two things. It was the greatest threat in 2010 and it's the greatest threat in 2014. It's the Treasury. 

It's no secret that there's no love lost between IDS and George Osborne. In Duncan Smith's ill-fated and brief stint as Tory leader, Osborne used to prepare him for Prime Minister's Questions. Now on equal footing in a Coalition cabinet Osborne has clashed constantly with his old boss. In his "inside story" of the Coalition government, In It Together, Matthew D'Ancona quotes the Chancellor as having told his aides that IDS is "just not clever enough". Then, in 2012, Osborne tried to rid himself of the turbulent minister and replace him with Chris Grayling, now Justice Minister. 

The Treasury has fought universal credit tooth and nail from the beginning. Why? Because, as a massive investment package for the poorest, it is expensive. Tapering off benefits puts pounds in people's pockets. It will cost the Government an estimated £2 billion. That is the price-tag of diminishing the disincentive to work, and even now there's a real risk that the Treasury may use the problems which have plagued the delivery of universal credit as an excuse to drop it altogether. 

Such an eventuality would be nothing short of disastrous. Not only would it ensure that "love" never catches up with "tough", but watering down universal credit would put us right back where we started — with a broken system, thereby scuppering the chance  genuinely  to impact the life-chances of men and women in Britain's most neglected neighbourhoods. 

The bishops have picked on the wrong minister. If Cardinal Nichols really wants to help the out-of-work, he should lobby George Osborne so hard that the Chancellor is forced to put out a restraining order on him. But the Archbishops of Westminster and Canterbury too should be ready to suffer the equivalent of political martyrdom in defence of Iain Duncan Smith.