I think this is what is known as taking the dignified way out, as opposed to the fate awaiting John Hutton, Tessa Jowell and probably Charlie Falconer when Gordo's first Cabinet is finally unveiled.
Armstrong is what I have always described as an absurd loyalist, namely someone who takes loyalty to the leader to the point of absurdity. Never was this more clear than in her conversation with the defecting Labour MP Paul Marsden when she actually uttered the phrase "We don't have spin doctors in Number 10 - or anywhere else."
The chances of her getting a Cabinet job under Gordon Brown were nil. The only thing to be said in her favour is that, unlike some of the others awaiting the axe, she had the good sense to realise this.