Brown by backing away from this confrontation has confirmed that he knows how weak he is. He has proved that he is a lame duck Prime Minister. Tony Blair's 'weak, weak, weak' jibe springs to mind.
Alan Johnson by taking the Home Office has bound himself in more closely to Brown. The rebels will now have to force a vacancy or a contest before Johnson can get into the game.
One of the key questions now is whether Labour backbenchers can see how disastrous it will be for the government to stumble on for the next year with a Prime Minister and Chancellor so lacking in authority.