Word is that Darling is staying put - if so, it would be the position of maximum weakness for Brown. It means he has had to abandon his plan to enstool Balls as Chancellor. And there was indeed such a plan - I know, for example, that Purnell was offered education, which suggests Balls was on the move. That was on Wednesday, the day Brown failed to back Darling in the Commons when Cameron asked him if Darling would survive the month. But Balls is so widely hated - and that letter (I hear) gathering signatures - that Brown figured he dare not. This, under the circumstances, is the safest option for Brown. But leaves him in the weakest possible position.