A display of weakness from Brown in the current circumstances would be provocative. But equally sending Balls to the Treasury, could be enough to tip some waverers into the rebel camp as well as triggering Darling’s resignation and possibly that of a couple of other Cabinet member: Remember Darling knows where the economic bodies are buried, the state of the books when he took on the job from Brown. I’m even hearing that some Treasury civil servants might speak out publicly about the mistakes of the Brown/Balls era at the Treasury if Balls is made Chancellor. (The Treasury is convinced that if Balls is sent there it will be to do another stimulus, something that could have catastrophic consequences for the public finances)
Brown has backed himself into a corner: if he moves Balls to the Treasury, the plotters benefit. If he keeps Darling there, his authority suffers a hammer blow. The one upside for Brown is that if he does get away with making Balls Chancellor it will reassert his authority or at least show that his Cabinet critics are all hat and no cattle.