Chris Mason: The anatomy of the prime minister's downfall

It was clear then, as we reported at the time, that this was unlikely to be the end of the matter – and so it proved. The elections in May solidified in the minds of countless MPs what many of them had long feared - their leader was deeply, deeply unpopular and costing their party support. The view of Labour MPs, channelling what they saw as the view of the electorate, calcified to a point where Sir Keir's imminent departure became near inevitable. Against that backdrop, he was powerless to prevent Andy Burnham contesting the by-election triggered in Makerfield in Greater Manchester to give him a chance to return to Westminster and take over as Labour leader. Now, at the end of a week in which the prime minister has set out a timetable for his departure and a newly re-elected Andy Burnham assembles a programme for government, we witness what remains of Sir Keir's government disintegrating before our eyes. The story of the public spat between the home secretary and the prime minister over the future of immigration minister Mike Tapp is a case study in discipline and coherence in government breaking down. Home Secretary Shabana Mahmood is furious that one of her junior ministers has, as she sees it, been insubordinate. Tapp is setting out his policy stall as Burnham, expected to be the next prime minister, thinks about who will get jobs in his new government. Tapp, incidentally, was super loyal to Sir Keir until the last. …